Module 5: Stand Establishment

Introduction

This module on Stand Establishment is divided into three lessons: Introduction to Forest Stand Establishment, Natural Regeneration Management and Artificial Regeneration Management.

This Module is the fifth in a series of Woodlot Management Home Study Courses produced by the Nova Scotia Department of Natural Resources

Lesson One - Introduction to Forest Stand Establishment

Forest stand establishment is a practice that ensures new healthy seedlings replace mature and over mature stands of trees as they are harvested. This Home Study Module will discus how natural and artificial regeneration techniques can maintain or improve the productivity of our woodlots by ensuring good stocking levels after harvest.

Successful stand establishment is the most important step toward good forest management. Without new seedlings, the site may not realize its full productive potential. It is similar to the carrot patch that has poor seed germination and produces more weeds than carrots; the garden is simply not as productive as it could be.

STOCKING

Stocking is the term used to describe whether there are enough trees per area and is usually expressed as a percentage. To better understand stocking, consider forest sites and stands as graphically comprised of square plots ( Figure 1 )

In Nova Scotia we usually plant seedlings and precommercially thin young stands to a spacing of approximately 1.8-2.4 metres (6-8 feet) between stems. Forest research indicates that these spacings are best for early tree growth and development for our average sites, tree species, and climate. Ideal spacing is 1.8m x 1.8m (6' x 6'), aiming for approximately 3,100 trees/hectare (1,210 trees/acre). This spacing provides young stands with 100 percent stocking and a good chance for survival during its first 40 years ( Figure 1 ). At narrower spacings, the trees have inadequate space and slow diameter growth. At wider spacings, the trees have too much space and will become limby and have less useable wood.

Each tree will develop and grow best if it is sufficiently free of competition from weeds and other trees for light, moisture and nutrients. When trees are taller than the competition, they are considered "free growing".

For plantations or naturally regenerated stands between one and 40 years of age, all plots must have one healthy, free growing tree for the site to be fully stocked ( 100%). A fully stocked area is fully utilized by growing as much wood as possible of a commercial tree species.

On the other hand, the site is only partially stocked if some plots are either barren or occupied by non-commercial species. Usually, partially stocked sites are expressed as a percentage. For example, if 1550 of the possible 3,100 plots/ha are occupied by commercial species, the site is 50% stocked and is only growing approximately 50% as much wood as possible.

However, openings on a woodlot may be desirable for wildlife. These areas will be used by many different species for feeding, hunting, and courting. Woodlots and Wildlife is the topic of Home Study Course Module IV.

In Nova Scotia, average sites with fully stocked stands can produce approximately one cord per acre per year for softwood species such as red spruce, balsam fir, and white spruce. Therefore, the softwood plantation or natural stand in ( Figure 1 ) should contain approximately 358 cubic metres/ha (40 cords/ac.) at 40 years. Hardwood trees produce less volume and generally fewer trees per acre than softwoods in a fully stocked stand because of the larger crown development. Softwoods have a more compact crown and use less energy to produce new needles annually.

It is important to understand stocking, site utilization, and the potential of sites to grow wood since these factors influence the establishment practices on our woodlots.

Cutting the forest without thinking about the next generation of trees can reduce the quality of the next stand. This cutting practice can develop into highgrading which removes the biggest and best trees and leaves poor quality trees to produce seeds. Highgrading is evident in all regions of Nova Scotia where there are now some stands of poor quality hardwood and softwood growing on sites previously occupied by more valuable species ( Figure 2 ).

Nova Scotia has approximately 30 native tree species. Ten of these will not be discussed because they are not common. Of the remaining 20 species, four have little commercial value, but play an important role in forest development and succession. They are striped maple, pin cherry, grey birch, and speckled alder.

Sixteen commercial species are listed in ( Figure 3 ), along with their relative percentages of total growing stock. Total growing stock is an estimate of the total standing wood volume in Nova Scotia. In 1987, this volume was estimated at 406 million cubic metres (112.3 million cords).

FOREST SUCCESSION

Have you ever wondered why one or several tree species occupy much of your woodlot? The answer may be that these trees are best suited and compete well in that particular woodlot environment. When discussing the environment of your woodlot, consider the climate, soils, topography, and site history. Together, these factors help determine the types of trees that grow on your woodlot.

Climate:
Is it hot or cold, wet or dry? As a very general example, Cape Breton Island and the Eastern Shore have hardy species such as balsam fir and black spruce because of a cool, damp climate and short growing season. Western Nova Scotia has a drier, warmer climate and a longer growing season which may favour red spruce, red oak, or white pine. The abundance of all native species varies throughout the province.

Soils:
Is the soil rocky? Does it contain well drained sandy loams or poorly drained clays, etc.? Pines regenerate, survive, and grow better on dry sites because they have a deeper rooting system than most conifers. They are commonly found on the dry, sandy loam of western Nova Scotia. Black spruce and larch can withstand excessive soil moisture better than other species and are found on many swampy areas throughout Nova Scotia. Black spruce and larch are also found on the better sites, but usually don't compete well with other species.

Topography:
Is your woodlot on a mountain top, close to a windswept seashore, or in a valley? Hardwoods are more likely to be found on ridges and hillsides, while softwoods are more likely to dominate valleys. Forests near shorelines are dominated by white spruce because they are able to withstand damage caused by wind and salt spray.

Site History:
Has your woodlot been burned, cut, farmed, or has it been undisturbed for the last 200 years? This history is often the major factor that relates to the present species and stand type. For example, white spruce regenerates quickly on abandoned fields and pastures throughout Nova Scotia, usually forming pure stands. It regenerates better than all other 19 tree species with grass on old fields or pastures. There is close to one million acres of white spruce on abandoned farmland in our province.

Most woodlots are usually made up of several stand types with various species and ages. Since artificial regeneration is a relatively new management tool in Nova Scotia, most stand types have become established from natural regeneration. These stands became established because the particular site history that existed favoured the development of certain species. In many areas you can stand on the boundary line separating two woodlots and see stands of completely different species composition; one side of the line can be 100% softwood and the other side 100% hardwood. The climate, soils, and topography on both sides of the line may be similar, but the site history has obviously been different.

Forest succession is the change in species composition, over time, as long-lived climax species replace short-lived pioneer species. There are several successional patterns in the forests of Nova Scotia. One example commonly found in the western area is shown in ( Figure 4 ).

In Nova Scotia there are many climax forest types made up of pure or mixed stands. Balsam fir dominates the climax forest types on the plateau of Cape Breton Island while red spruce dominates the climax forest types of mainland Nova Scotia.

The introduction of beech bark canker in the early 1900's has removed beech from the climax position that it once held. Sugar maple and yellow birch now occupy a climax position in our forests.

To help understand forest succession and why forests often change species after disturbance, 20 tree species are grouped into five classes, based on their ability to survive and grow in shaded conditions, known as shade tolerance ( Table 1 ). It is important to understand shade tolerance to understand where each species fits into forest succession. You will then begin to understand why your woodlot reacts and develops as it does over time. Please study Table 1 carefully.

The following is an example of how the shade intolerant-tolerant relationship works with natural succession.

In a two-story stand, shade intolerant species usually overtop the shade tolerant ones. On your next walk in your woodlot, compare the trees in the top canopy of a two-story stand to those in the bottom. You will generally find intolerant species such as aspen, white birch, or larch above balsam fir or red spruce. You will never find aspen, white birch, or larch growing under other trees.

( Figure 5 ) illustrates this situation and gives some of the reasons why shade intolerant species usually become established before shade tolerant ones.

Using the shade tolerance ratings in ( Table 1 ), our potentially most valuable trees occupy the middle to late stages of succession.
* intermediate species - white pine, white ash, red oak.
* tolerant species - red spruce, black spruce, white spruce, yellow birch
* very tolerant species - sugar maple
On the other hand, our least valuable trees for forest fibre products dominate the early stages of succession.
* intolerant species - white birch, aspen, larch, pin cherry, grey birch, alder

This explains why our forest management programs modify, as much as possible, the earliest stages of succession. This is accomplished by using either natural or artificial regeneration management techniques.

Forest management programs aim to produce healthy, productive forests capable of yielding increased volumes of high quality products. Consideration is also given to the maintenance of enhancement of fish and wildlife habitats, water quality, and recreational opportunities.

STAND ESTABLISHMENT IN NOVA SCOTIA

The main priority of our stand establishment practices is to ensure that the percentage of high value species is maintained or increased on our woodlots. In 1987, approximately 54 percent of our forest growing stock was made up of our most desirable species ( Table 2 ) .

From a stand establishment perspective, where do you begin? Start first by examining your land to see what is there. Does your woodlot have the following:

(1) old stands
(2) poorly stocked stands
(3) young, immature stands with species of very low value

If your woodlot has these types of stands, you may want to consider stand establishment techniques to improve productivity. The easiest way to get started may be to get help from forestry personnel from the Department Natural Resources, a Forest Group Venture in your area, or an approved forestry consultant. They can help develop a management plan for your woodlot. The plan will identify similar stand types and provide for your woodlot. The plan will identify similar stand types and provide information on species composition, tree heights, ages, percent stocking, wood volume per area, stand condition, maturity, and regeneration stocking by species.

Typical stands that should be replaced with more valuable tree species are:

(1) "Old" stands (mature-overmature)

Example:
Balsam fir and white spruce stands will normally show a significant decline in growth by 40 years and may be considered mature. At age 60, they are usually overmature and may have started to deteriorate.

Trees can live longer than the average ranges outlined in ( Table 3 ). However, at some point they begin to decline, resulting in butt rot, dead tops, blowdown, and reduced height and diameter growth. At the older stage, it is more productive to harvest and ensure that the trees are replaced with healthy, young trees of good desirable species. The old saying "the timber on my woodlot is as good as money in the bank" may or may not be true, depending on whether your forest stands are growing (appreciating in value) or declining (depreciating in value).

(2) "Poorly stocked" (understocked) stands of any age

Example:
A well stocked stand of red spruce 40 years old will normally have 3,100 trees per hectare. A 40 year old red spruce stand that has had only 741 trees per hectare from the beginning will be poorly stocked stands should be replaced, regardless of species.

(3) Immature stands with "low value" species

Example:
Immature grey birch and aspen stands have very low commercial value and limited market opportunities in Nova Scotia. This is not likely to improve in the future. If these stands occupy a significant portion of the woodlot, it may be the best to salvage any usable wood and restock the site with more valuable species.

Now that we have a general idea of which stands should be considered for stand establishment techniques, and assuming our objective is to grow primarily the most valuable species, what are the alternatives? How should clearcuts, partial cuts, shelterwood, or seed tree treatments be used? Should we plant after cutting or will natural regeneration restock the site?

The next two lessons will attempt to answer these questions by describing the common mature to overmature stand types on small woodlots in Nova Scotia and how to regenerate them.

Module 5 - Lesson One Quiz

Questions:10
Attempts allowed:Unlimited
Available:Always
Pass rate:75 %
Backwards navigation:Allowed

Lesson Two - Natural Regeneration Management

Natural regeneration develops when seeds from surrounding trees fall to the forest floor or stump sprouts and root suckers develop on some hardwoods. This and other methods of reproduction are illustrated in ( Figure 6 ). To regenerate our forest stands naturally, it is necessary to understand the strategy for survival of each tree species.

STRATEGY FOR SURVIVAL

For each tree species we need to know:

  1. At what age will a particular tree begin producing seed crops?
     
  2. How often do good seed years occur?
     
  3. How far can seeds travel from the parent tree either by wind, squirrels or birds?
     
  4. Once on the forest floor, how long will the seed remain good (viable) - a few weeks? a year? several years?
     
  5. What type of seed bed is preferred by each species? How much moisture is required?
     
  6. How much sunlight (full versus partial) is required to keep seedlings alive and growing? Are young seedlings usually present as advanced regeneration in mature and overmature stands?
     
  7. Is the species capable of vegetative reproduction (sprouts, suckers)?
     
  8. Using the answers to these questions, what cutting strategy can be used to ensure that the new stands will contain sufficient numbers of our preferred species?

Table 4 ( One + Two ) helps answer these questions by providing information for seven preferred species, as well as two aggressive competitors. If this all seems to complicated, we will help you so that it won't be complicated at all.

The requirements for healthy seedling production for the seven preferred species are very similar. In general:

  1. With the exception of yellow birch and sugar maple, they all begin producing good seed crops between 40-50 years of age. Smaller amounts of seed can usually be produced before these ages. Obviously, if stands are cut before optimum seed-bearing age, the chances of regenerating these species are reduced.
     
  2. With the possible exception of red spruce, we can expect good seed crops at least every five years. This is not a long time in the life of a forest.
     
  3. Most species have seed which are small enough to be carried by wind up to several hundred feet from the parent tree. Red oak seed are too large to be windblown.
     
  4. Their seeds all mature in early fall and spend the winter on the forest floor. Germination will occur in the following spring if the seed is good and it has landed on a suitable seedbed. Seeds are usually good for one year with the exception of black spruce, white ash, and yellow birch. Black spruce cones open slowly and can protect the seed so it may remain viable for several years, while yellow birch and white ash may remain viable for two years.
     
  5. All seven species are intermediate to very tolerant of shade. Except for pure stands of white spruce and black spruce, these species will regenerate from seed with some form of shelterwood system.
     
  6. All species prefer mineral soil beds, but frost heaving can be a problem. A mixture of mineral soil and humus is the preferred seedbed because it is less likely to dry out in the summer and is the best medium for roots to extract nutrients and water. Sugar maple and white ash have an advantage with their large taproots that can penetrate leaf litter on the forest floor, whereas the other species cannot. Skidding with horses and winching with farm tractors or skidders is an excellent way to mix mineral soil with humus in shelterwood cuts.

These points show some of the similar characteristics which exist for the seven tree species covered in Table 4. As summarized, most of these species will regenerate after some form of shelterwood system. However, this does not eliminate the possibility of using alternate forms of clearcuting, selection, or seed tree systems.

The final decision would also need to consider other information; such as, the woodlot owner's objectives and the required volumes or stocking levels needed for the treatment to be successful.

Clearcutting is the most common method of harvest. It can provide an opportunity for other tree species listed in Table 4. In 1987, red maple made up 15 percent and balsam fir made up 18 percent of the total growing stock in Nova Scotia and both are increasing at the expense of more valuable species.

Let's summarize the factors from Table 4 that enable red maple and balsam fir to be so competitive.

Red Maple

Balsam Fir

Unlike red maple which starts quickly after disturbance, balsam fir's strategy for survival usually begins long before any disturbance takes place. Balsam fir produces seed at an earlier age than most of its competitors. The seedlings can survive for many years in the understory of most of our forest stands, ready to take advantage of any openings created in the overstory.

If you want to reduce balsam fir and red maple on your woodlot, practice shelterwood cutting to ensure adequate regeneration of other tolerant species. Later, precommercial thinning of the young trees can favour the most desirable species.

If your area is dominated by balsam fir, you may want to adopt a modified management strategy to optimize the use of this species.

Let's now discuss the different cutting systems that are available to establish natural regeneration. The following descriptions of the shelterwood, clearcutting, selection, and seed tree methods are simplified versions of those previously discussed in the Woodlot Management Homestudy Course entitled " Harvesting Systems. "

As a good example, the shelterwood system will be discussed in slightly more detail to illustrate the establishment of natural regeneration.

SHELTERWOOD CUTTING SYSTEM

The following is a simplified version of shelterwood cutting as previously discussed in the Home Study Course module entitled Harvesting Systems.

Shelterwood cutting is the removal of mature timber in two or three partial cuts which extend over 10-20 years. The system encourages evenaged regeneration of preferred species under the partial shade of valuable seed trees. ( Figure 7 ) illustrates the shelterwood cutting system.

The 30-50 percent basal area removed in the first cut is designed to:

To better understand the effect of shading on the forest floor, compare the edge of a 5-10 year old clearcut to a dense stand of shade tolerant trees ( Figure 8 ). Forest stands along roadways can also provide an excellent opportunity to view the benefits of shading.

Shelterwood cutting uses partial shading to give the more valuable species the competitive edge at the seedling stage. When the seedlings become well established, the overstory can be removed. Well established softwood seedlings are at least 0.3 m (1 ft) tall with firm roots in mineral soil. The seedlings are now able to hold their own against the competition and grow best under full sunlight.

Shelterwood cutting is a very good way to promote natural regeneration of desirable species. Here are some guidelines that can improve the prospects for success.

Pre-cut Stand Assessment:

Walk through the stand before you begin cutting. Note the regeneration; check the forest floor closely since some seedling, such as red spruce, are very small. Also note potential seed sources of the most valuable species. Assess site and stand conditions and make a mental plan of how you will proceed to :(a) minimize damage to existing desirable regeneration and (b) encourage additional regeneration establishment. Refer to ( Figure 8 ) for help.

First Cut:

Second Cut

Final Cut

Follow-up Treatments

Conduct a weeding operation within 3-5 years of the final harvest. Cut stump sprouts and other regeneration of above average height that overtop the desirable regeneration. Leave 1-2 stems per stump to help control resprouting ( Figure 10 ). It is important to delay this weeding operation until the sprouts and suckers begin to seriously interfere with seedlings.

Finally, since these naturally regenerated stands will usually have too many seedlings for good stand growth and tree form, a precommercial thinning may be required. A precommercial thinning generally starts when the trees are 2 m (6 ft) tall in stands dominated by softwoods and 6m (20ft) tall in stands dominated by hardwoods. It is best to wait longer before spacing hardwoods to let the crop trees develop at least one log length of clear wood. Hardwoods are spaced wider than softwoods because they are older when thinned and additional space is needed to maintain good diameter growth.

CLEARCUTTING

Clearcutting is the removal of all, or most, of the trees on a piece of forested land during one harvest operation. It is the most common method of harvest used in Nova Scotia.

Clearcutting is an evenaged form of management because most of the trees that are cut are the same size and age.

Fortunately, our climate is very favourable for tree growth. As such, 67% of all clearcuts regenerate naturally to commercial species. In those areas that either do not or cannot regenerate naturally, artificial regeneration may be needed.

When applied properly, clearcutting is a safe and effective way to manage your stands. It is suited to stands of overmature trees; areas extensively damaged by fire, insects, diseases, or wind;; and stands that have been highgraded or are composed of poor quality trees. Before clearcutting, an assessment should be made of the existing regeneration and a forecast made for possible seedling establishment after the cut.

Alternate clearcutting methods also include strip and patch cuts which encourage natural regeneration establishment. As previously noted, more information on these alternatives is given in an earlier Home Study Course module.

SELECTION CUTTING SYSTEM

Selection cutting is the removal of trees from a stand to provide a steady flow of forest products from the woodlot. This unevenaged management system can remove single trees, groups of trees, or strips of trees from a stand. It differs from shelterwood cutting and clearcutting which are evenaged management systems.

Selection management should not be confused with diameter-limit cutting in which trees less than a certain diameter are not harvested. This can result in "high-grading" where you "take the best and leave the rest" because the small trees are not always young ones.

Selection cutting is a complicated system which combines aspects of shelterwood cutting, precommercial thinning, and merchantable thinning to maintain stands with trees in at least three age classes.

Unfortunately, selection management has its disadvantages. Compared to the even-aged cutting practices, this system requires more skill when selecting trees to be cut. Selected trees need to be good quality, tolerant, and long-lived (80+ years) species that are windfirm and able to survive with less than full sunlight.

An extensive road and trail network are also required to remove the low volumes on each acre.

If you want to try the selection system on your woodlot, ask forestry personnel for help.

SEED TREE SYSTEM

This method of stand establishment is a modification of clearcutting, except that scattered good quality, mature trees are left to provide seed for a new crop.

This system can be used very successfully to regenerate white pine in Nova Scotia. For white pine, leave 20-30 good quality, healthy seed trees per hectare (8-10 trees per acre), preferably in semi-straight rows, to make future cutting of the seed trees easier when regeneration becomes well established. White pine is suited to this system because it is a very windfirm species.

The follow factors allow white pine to regenerate and compete after clearcutting:

  1. Its intermediate shade tolerance allows it to compete with species such as raspberry, pin cherry, and hardwood sprouts which usually regenerate clearcuts.
     
  2. It usually grows on poor, dry sites where there is less competition with other tree species and shrubs than is on fertile sites.

Regardless of which harvesting system is used to promote natural regeneration, it is important to do a pre-cut stand assessment to determine which system is best for your woodlot.

STAND TYPES SUITABLE FOR NATURAL REGENERATION MANAGEMENT

Here are some examples of common mature and over mature stand types that are suitable for natural regeneration management and the results that can be expected from a shelterwood cut.

Red Spruce Stands

Red spruce is a valuable tree in Nova Scotia. It responds well to natural regeneration management. Stands may be pure red spruce or comprised of at least 30 percent red spruce.

Sample stand types are:

As ( Table 3 ) in Lesson 1 indicates, red spruce usually matures in 80-100 years. There are a few situations where red spruce stands begin to deteriorate at 40-50 years. In these stands, shelterwood cutting should be started early. These include:

  1. some old pasture lands where red spruce has developed excessive butt rot
  2. stands in poor health because of porcupine or insect damage
  3. stands with greater than 40 percent short lived species, such as balsam fir, aspen, and larch.

Where it occurs naturally in Nova Scotia, red spruce regenerates well when the shelterwood method is used. Usually, the forest floor under mature red spruce stands is covered with tiny red spruce seedlings from previous seed years. Our major objective in these stands is to ensure adequate sunlight for good seedling growth. In many cases, the first and second cuts of the shelterwood system can be combined and the period from the initial to the final cut may be within 5-10 years. In stands where red spruce is mixed with shade tolerant species such as eastern hemlock and sugar maple, crown closure is usually so tight that red spruce regeneration is unlikely to become established. In this situation, the shelterwood process will require three cuts as noted in ( Figure 7 ).

In red spruce stands with a high proportion of balsam fir, the regeneration may be dominated by the more competitive and generally larger balsam fir seedlings. A precommercial thinning which favours red spruce can change this situation. In some instances, young stands with high proportion of balsam fir can be converted to primarily red spruce. For example, a 1.8 x 1.8 metre (6 ft. x 6 ft.) plot may have nine balsam fir seedlings and one red spruce seedling before precommercial thinning, but only the red spruce seedling after precommercial thinning.

Red spruce does not occur extensively on Cape Breton Island because of the generally harsh, cool climate. Some red spruce planted on well drained, sheltered sites, such as inland valleys, is expected to grow reasonably well.

There are many hardwood stands that are well stocked with red spruce regeneration of various sizes. The seeds may have come from scattered reed spruce trees either in the stand, in red spruce stands nearby, or in many cases, from the trees that were removed.

Gradually opening these stands through shelterwood cutting will allow them to convert to predominantly red spruce. These types of stands show us the importance of pre-cut assessments for good stand establishment techniques.

Balsam Fir Stands

These stands may be pure stands of balsam fir or stands where balsam fir is the major species.

Sample stand types are:

Balsam fir stands tend to develop well after a clearcut since advanced regeneration is usually present. This regeneration is present because balsam fir produces seed at an early age and generally begins to deteriorate before reaching 40. Only in limited areas, such as the Cape Breton Highlands, can balsam fir remain healthy for longer periods of time.

Shelterwood cutting is not necessary for balsam fir stands. To establish a stand on a woodlot dominated by balsam fir, you could:

White Pine Stands

These are pure stands or mixed stands where white pine comprise a major component.

Sample stand types are:

White pine regenerates very well in Nova Scotia when one of the following systems are used:

  1. shelterewood system
  2. clearcutting with seed trees (20-30 trees/ha or 8-12 trees/acre)
  3. clearcutting immediately following a good seed year

Intermediate in shade tolerance, white pine seed can germinate and grow under partial shade created by the shelterwood system or under full sunlight created by clearcutting. Adequate soil disturbance provided by skidding or winching will help improve regeneration results, regardless of which system is used.

White pine weevil is a very serious pest that usually makes its home in the leaders of the largest, fastest growing trees. Affected trees become crooked and are generally worthless. When these stands are between 6-9 metres (20-30 feet) tall, a precommercial thinning can reduce the impact of weevil damage. Cut the deformed trees and favour straight-stemmed, co-dominant and intermediate trees, spacing the trees approximately 2-3m (6-10 ft) apart.

White pine has traditionally been a valuable tree. Managing individual trees or stands of white pine by using good stand establishment techniques, weevil control, thinning, and pruning to produce clear wood may bring worthwhile benefits to woodlot owners in the future.

Tolerant Hardwood Stands

These may be pure stands of sugar maple or stands of sugar maple mixed with yellow birch, beech and lesser amounts of red maple, white birch, white ash, eastern hemlock, red spruce, and striped maple.

Sample stand types:

Our general objective in managing these stands is to grow straight, clear stems of sugar maple, yellow birch, and white ash to a diameter of 30-35 cm (12-14 in.). Hardwood logs reach their maximum value when the diameters are equal to or greater then about 32 cm (13 in.). Fully stocked tolerant hardwood stands with an average diameter of 32 cm (13 in.) will have approximately 350 trees/ha (140 trees/ac.).

These species usually begin to mature at 80 years ( Table 3 ), at which point regeneration establishment can be considered at an earlier age for poor quality stands with less than 200 stems/ha (80/ac) of yellow birch, sugar maple, and white ash.

Sugar maple and white ash have large seeds and require similar seedbeds. Their seedlings can penetrate hardwood leaf litter (matts). Yellow birch has very small seed and may require some soil disturbance provided by skidding or winching trees to create suitable exposed mineral soil.

( Figure 7 ) gave a general idea of the shelterwood cutting method presently recommended in Nova Scotia. In hardwood stands, more volume is removed in the first cut than from softwoods. With hardwoods, the release cut can be omitted in favour of the final cut when the average height of the regeneration is 0.5-1.0m (1.5-3 ft.). The ideal time for the final cut is when most seedlings are more than 0.5m (1.5 ft.) tall and have shown growth of at least 15 cm (6 in.) during the previous growing season. These seedlings will be well established and will no longer need the benefit of overhead shade, but are still small enough the risk of damage during final felling will be low.

Since sugar maple, white ash, and red maple are vigorous stump sprouters, sprout control is very important if the new stand is to be well stocked with young trees of seed origin. Sprouts can quickly outgrow seedlings. Three years after final harvest, a sprout may be 3m (10 ft.) while a seedling may be about 0.5-1.0m (2-3 ft.).

Expect young hardwood stands to be approximately 12 meters (40 ft.) tall at 40 years, at which time a second thinning will be required to maintain good diameter growth.

Module 5 - Lesson Two Quiz

Questions:10
Attempts allowed:Unlimited
Available:Always
Pass rate:75 %
Backwards navigation:Allowed

Lesson Three - Artificial Regeneration Management

Artificial regeneration of softwood begins when cones are collected from the forest or from special seed production areas called seed orchards. Seed orchards contain trees grown from seed or shoots from the very best trees, often called "plus" trees. The seed are extracted mechanically and stored under controlled conditions.

Seeds are germinated and grown into seedlings in forest nurseries. Softwood species dominate artificial regeneration programs. Hardwood seedlings are more difficult and expensive to produce and planting success is poor. This text will deal exclusively with planting softwood.

In 1989, approximately 10 million trees were planted on small woodlots in Nova Scotia. At 3100 trees per hectare (1200 trees/acre), these trees occupy about 3,400 hectare (8,300 acres). In addition, approximately 15 million trees were planted on crown and large company lands in 1989.

An owner whose woodlot is dominated by healthy red spruce, yellow birch, sugar maple, and beech may not understand why we need to plant so many trees. This is especially confusing when it seem that the forest can regenerate itself, as discussed in Lesson 2. The forests of the province can be quite different from one area to the next. A woodlot owner in Cape Breton whose balsam fir and white spruce stands have been devastated by spruce budworm and spruce bark beetle during the past 155 years may not have an option other than to clearcut the site and replant to restore productivity.

Planting is usually recommended on private woodlots in the following cases:

  1. mature and overmature stands that will not likely regenerate naturally, such as white spruce, or that will regenerate to undesirable species.
     
  2. non regenerating, understocked, stands, regardless of species composition, since the site is not being fully utilized, if it will not likely improve.
     
  3. young stands stocked with low value species such as grey birch, white birch, aspen or beech.
     
  4. stands that have been damaged by insect, disease or fire and which will not regenerate naturally.

PLANNING

As with natural regeneration, the most important thing to do before making the final decision to plant is to walk though and thoroughly assess the stand prior to harvest. This will:

Note:
All softwood and mixedwood cutovers must be left for two years before planting to eliminate the risk of damage by the seedling debarking weevil which lives in new slash. This will also provide an opportunity for natural regeneration to become established.

Use the following criteria to decide which method of harvest may be best when site preparation and planting are included as part of the total operation:

Ecologically
Which method will minimize site disturbance and nutrient removal and reduce the risk of fire?

Financially
Which method will pay the highest stumpage rates and result in the lowest future treatment costs (e.g. site preparation)?

Technically
Is there sufficient landing space for the various logging systems available?
Is risk of seedling debarking weevils high?

Finally
What type of harvest is best for your particular stand versus what is available? Do you have a choice?

If your assessment indicates planting is needed, plan for the following aspects of the operation:

(a) harvesting method
(b) site preparation
(c) planting
(d) plantation maintenance and weeding

Good planning may allow you to do something at one stage that will make future treatments easier and cheaper. The most successful artificial regeneration efforts usually begin with a well planned harvest operation. As an example, you may be able to harvest in a way that will eliminate the need for site preparation.

Now let's discuss these aspects of artificial establishment of a stand.

Harvesting Method

In Nova Scotia, harvesting is carried out in one of the following methods:

  1. Whole-Tree Harvest: Trees are felled, skidded or forwarded to roadside, with limbs and tops, leaving a relatively bare site.
     
  2. Shortwood Harvest: Trees are felled, delimbed, and bucked to length at the stump leaving limbs and tops on the site. Wood is carried to roadside by a forwarder or tractor-wagon.
     
  3. Tree-Length Harvest: Trees are felled, delimbed, and skidded tree length to the landing.
     
  4. Random-Length logging is a system similar to #3. Random-length products are skidded or forwarded to a landing.

Site Preparation

The primary objective of site preparation is to create as many suitable planting spots as possible. Suitability for planting means easy access for planters and sufficient suitable microsites for seedling survival and growth. These microsites generally have adequate drainage, mineral soil and humus mixture, and minimal weed competition.

Sites logged using the whole-tree harvest system may not require site preparation because the site is generally clear of logging slash. On sites logged using the shortwood or tree-length systems, limbs, tops, and unmerchantable debris may hamper the ability of planters to reforest the area. In this case, slash must be reduced or rearranged by one of the methods shown in ( Figure 11 ).

The brushrake and burn system was the site preparation method most widely used in Nova Scotia. The popularity of this system has declined because of concerns about fire hazards and nutrient loss associated with burning. The debris crushing system and corridor raking will likely become more popular since most logging debris stays on the site. The possible serious environmental impacts, including nutrient loss from whole tree harvesting, is a concern for both public and some forestry experts.

Planting

Lesson 1 described how each tree species competes under a particular set of site factors which include drainage, fertility, competing vegetation, and exposure. When deciding which species to plant, consider the site factors and choose the species that are likely to compete and grow best under the existing conditions.

A general guideline of species selection is given in ( Figure 12 ).

The following are examples of species that will do better on well drained, fertile sites, but due to their silvic requirements, they can survive on these less favourable sites.

If the site is not suited to the species you prefer to plant, site improvements can be made by:

Nursery Stock

When you have decided which species to plant, the following nursery stock types may be available:


  • best on sites with little or no vegetation and shallow duff layer
  • easiest stock to plant, especially on very rocky and stony sites
  • plant using a hoe pipe or dibble

  • stock similar in size to container
  • best on sites with moderate duff depths,few rocks and with little vegetation.
  • plant using shovel or Wifsta hoe

  • large sturdy stock, but expensive to grow and plant
  • best on sites with competing vegetation or on bare mineral spots to help reduce frost heaving
  • plant using shovel or Wifsta hoe

  • best on sites with little or no vegetation and shallow duff layer
  • easiest stock to grow, especially on very rocky and stony sites
  • plant using a hoe pipe or dibble

Planting Spot Selection

Planters ultimately decide where each seedling should be planted. The following are general guidelines for choosing suitable planting spots or microsites:

Timing

Choosing the best time of year to plant will help increase the chances of success. Adequate soil moisture is the most critical factor affecting early survival and growth. For best results, plant in the spring soon after the frost leaves the ground (April 15-June 15) or in late summer (August 1 - September 15). Avoid planting during the potentially hot, dry period of early summer.

Seedlings planted after mid-September have less time to establish their roots and become more susceptible to winter drying or burning from insufficient snow which protects seedlings from winter winds.

Additional Planting Considerations

1. Markets
It is difficult to predict the changes in markets in 30-40 years. Red pine and larch currently have low market potential. However, specific products from these trees may have future possibilities. For example, good quality red pine trees will always be in demand for utility poles.

2. Old Fields
Grassy fields and pastures provide heavy competition for seedlings. Without using site preparation such as ploughing, white spruce and Norway spruce are the best choices.

3. Insect Damage
Are there common insects or diseases in your area?

White pine weevil occurs throughout the province and can severely affect young, healthy trees. Planting seedlings close together may help to reduce this problem, but will not eliminate it. You may want to discuss the situation with a local forester or forest technician.

As mentioned earlier, some areas of Nova Scotia have a small insect called "Hylobius congener" or "seedling debarking weevil" which causes severe damage in some newly established plantations. The weevils are attracted to newly logged areas and feed on the inner bark of freshly cut stumps and slash. When this food source disappears, the weevils turn to other food sources, which may be newly planted seedlings. Their feeding usually girdles the small seedlings which then die. In central Nova Scotia where the risk of weevil is high, logged areas are not replanted for at least two years after cutting. This gives the weevils time to eat and leave the site. Most forestry personnel in Nova Scotia are aware of the problem and can tall you how to proceed, depending on weevil risk in your area.

Plantation Tending

When seedlings are established, plantations should be tended to ensure that the young seedlings are sufficiently free of competition to grow properly. This is especially important during the first 5-10 years until the plantation is at a "free to grow" stage.

The establishment of plantations is similar to the pioneer stage of succession. After the mature trees are harvested, plants and shrubs will try to become established on the site. Examples of this vegetation include raspberry, grass, pin cherry, alder and aspen.

Let's look at the two types of competition that may affect young planted seedlings.

Competition for Space

Competition for Light

In Nova Scotia, ground or aerial application of registered herbicides is the most commonly used method of weed control in plantations. It is both economical and effective.

There are presently two types of herbicides registered for forestry use:

  1. Root uptake herbicides such as Velpar L (Hexazinone) and Princep Nine-T (Simazine) are most commonly used for weed control before planting. These are applied in early spring when plants begin to grow. They work best if applied to just before light rains which moves the herbicide into the soil where it is taken up by the roots.
     
  2. Leaf intake herbicides such as Vision (Glyphosate) are usually applied in late summer (August-September) when softwoods have hardened off and are dormant. Hardwoods and other herbaceous plants are still actively growing and are killed by the application of Vision. This releases the conifers from the overtopping cover of weeds during the next growing season.

Chemical weed control reduces, but does not eliminate, the competition for light and space and gives the planted seedlings room to grow.

Manual weed control is not as effective or as feasible as herbicides since most competing vegetation sprout vigorously after cutting. Manual weeding would likely need to be repeated several times to ensure plantation success. Usually, herbicides need only be applied once during the life of a forest stand (40-80 years depending on length of the rotation).

APPLYING THEORY TO PRACTICE

Finally, let's look at two of the most common stand types that require a regeneration management strategy to guarantee productivity for the next rotation.

1. "Budworm damaged balsam fir and white spruce stands in Cape Breton"

Typical mature and overmature balsam fir and white spruce stands are 30-70 percent dead and have been dead for 4-5 years (in 1989). As these stands break up, light reaches the forest floor to allow establishment of patchy regeneration, and bare patches, these stands are a real mess. Well prescribed plantation management strategies for these bud worm damaged stand begin by:

(a) Developing a plan before harvesting:

The stand should be divided into two distinct operating areas if possible, based on a pre-harvest stand assessment.

Block 1: Area with satisfactory stocking of desirable regeneration.

Block 2: Area not satisfactorily stocked to desirable regeneration.

Each block needs to be large enough to make the operation economically feasible, 2-4 ha (5-10 ac).

(b) Harvest

Block 1: Organize felling and wood extraction to minimize damage to existing regeneration. Decide whether crushing the debris by dozer or roller will benefit future thinning operations, without seriously damaging the regeneration.

Block 2: Organize felling and wood extraction to facilitate efficient site preparation.

(c) Site Preparation

Block 1: Crush debris if beneficial; if not, leave as is.

Block 2: Brush rake debris into corridor piles or wait at least one year to use a crushing roller. Leaving slash to rot for 2 years can greatly reduce site preparation costs and result in a better job. If necessary, apply a root uptake herbicide such as Velpar L before planting to control competition.

(d) Planting

Order planting stock six months or more in advance for best selection. Order white spruce, Norway spruce, or white pine for sites with well drained soils; red spruce for well drained, sheltered sites (Cape Breton only); and black spruce for sites where drainage tends to be poor. Container or jiffy pot seedlings are preferred for ease of planting; small bareroot stock is second choice; and large bareroot stock should be planted where weed competition is expected to be a problem, Plant at 1.8m x 1.8m ( 6 foot) spacing as soon as the ground thaws in the spring.

(e) Weeding

Assess plantation annually for weed problems. Carry out chemical weed control if seedlings are suffering from competition. Use one application of a leaf absorbed herbicide such as Vision in late August or September to reduce competition. Continue yearly assessments until the average height is 2 m (6 feet)and use chemical or manual weed control as necessary. Plantation is now "free to grow" to age 30-40 years at which point a merchantable thinning may be required.

2.  Mature to Overmature "White Spruce Stands"

White spruce stands begin to show reduced growth and decline between 40-60 years of age. In Nova Scotia, white spruce stands do not usually regenerate naturally to white spruce with either shelterwood cutting or clearcutting. Therefore, clearcutting and planting are usually recommended in mature to overmature white spruce stands, preferably following these five steps to successful plantation establishment.

(a) Develop a plan before harvesting:

Do a pre-harvest stand assessment. Is desirable regeneration present? Occasionally, white spruce stands regenerate to red spruce, balsam fir, white ash, or sugar maple if a seed source is available. If desirable regeneration is present and the area is sufficient, divide the stand into two operating areas - Block 1 and Block 2 - and follow the previous suggestions for budworm damaged stands.

(b) Harvest

Ensure that the favoured method of harvest is organized to make future operations as efficient and effective as possible. Good wood utilization and minimal site damage will help at the site preparation stage, if necessary.

(c) Site Preparation

(d) Planting

Order trees in advance. Select the best species to match your site. Choose the appropriate stock type unless land classification indicates otherwise.

(e) Weeding

Follow the 1 (e) suggestions for weeding in budworm damages stands.

Summary and Review

( Figure 13 )  will help you decide which stand establishment practices are best suited for your woodlot.

Forests generally grow slowly. It can take 40-60 years for a tree to mature. Stand establishment and development processes that occur on your woodlot will take time to see and understand. Carefully watch and note the effects of cutting and natural succession. Discuss your own particular situation with forestry personnel. You will begin to understand and apply this knowledge to improve the management of your woodlot.

Module 5 - Lesson Three Quiz

Questions:10
Attempts allowed:Unlimited
Available:Always
Pass rate:75 %
Backwards navigation:Allowed

Woodlot Management Exercise

Let's look at a sample woodlot that has three distinct stand types and determine the site history of each type based on what we know about the strategy for survival for each species. Based on what you have just read and your own experiences, what would be the site history and stand establishment recommendations for the following three stands?

STAND 1:

40 year old evenaged stand 90% white spruce; 10% balsam fir, grey birch

Site History _________________________

Stand Establishment Recommendations		 _________________________

STAND 2:
20-50 year old unevenaged stand 70% red maple, white birch, beech; 20% balsam fir; 10% red spruce, yellow birch, sugar maple

Site History _________________________

Stand Establishment Recommendations		 _________________________

STAND 3:
80 year old evenaged stand 70% red spruce, eastern hemlock, 20% yellow birch, 10% red maple, white birch

Site History _________________________

Stand Establishment Recommendations		 _________________________

 

Suggested answers

List of Tables

 
Table 1 Shade tolerance and forest succession relationships of Nova Scotia trees
 
Table 2 Commercial tree species priority based on potential economic value and growing stock percentages
 
Table 3 Average range of maturity for commercial species in Nova Scotia
 
Table 4- (1)
Table 4- (2)

 

List of Figures

Figure 1 Graphic view of forest plantations and young stands
 
Figure 2 Site production between good and poor stand establishment practices
 
Figure 3 Total growing stock percentages for 16 native trees
 
Figure 4 Sample of forest succession found in Nova Scotia
 
Figure 5 Early stand development of shade intolerant and shade tolerant species
 
Figure 6 Methods of natural regeneration
 
Figure 7 Shelterwood cutting system
 
Figure 8 Shade zone effects on forest floor vegetation
 
Figure 9 Comparison of red spruce seedling growth at two different
 
Figure 10 Manual cutting to control sprout dominance
 
Figure 11 Site preparation equipment used prior to planting
 
Figure 12 Species to plant
 
Figure 13 Stand establishment flowchart (** Abbreviations explained)
   
   
   
   
 

 

Suggested Answers

Stand 1

Site History
This stand was likely an abandoned field or pasture that has become a white spruce forest. Signs include the large amount of white spruce that borders the homestead surrounded by rock walls and wire fence. You may want to check the surrounding soil. It it is flat, it may indicate earlier farm cultivation.

Recommendation
Table 3 tells us that white spruce stands generally mature between 40-60 years. This stand is likely mature or nearly mature and should be harvested within the next 20 yeas as it begins to show signs of decline. White spruce stands usually do not regenerate well even with shelterwood cutting. The forest floor should be assessed for existing natural regeneration before harvesting. tHe stand will likely need to be planted.

Stand 2

Site History
The unevenaged condition and pioneer species such as white birch and pin cherry indicate that cutting took place in this stand 20-50 years ago. The presence of shade tolerant species like red spruce, yellow birch, sugar maple, and beech shows that the site was probably dominated by these species in the past. Historically, stands closest to the homestead were used for fuelwood. Some pulpwood or logs were also cut each winter for extra cash.

Recommendation
This stand is generally immature and should only be considered for stand establishment if significant areas are either understocked or occupied by low value species. If either of these situations do exist, assess the site for desirable natural regeneration. A release cut can be done if adequate regeneration is present. If regeneration stocking is inadequate, it may be best to clear the site and plant more desirable species. If the stand is adequately stocked with good quality trees, thin the dense areas to favour the desirable species. Otherwise, this stand could be left to grow for 10-20 years then reassessed for stand establishment practices.

Stand 3

Site History
The stand is evenaged and likely resulted from a clearcut. Red spruce, eastern hemlock, sugar maple, yellow birch, and beech advance regeneration were probably present in the original stand. The red maple may have originated as sprouts, but like the white birch, may have seeded in on logging trails or openings. The advance regeneration of the shade tolerant trees died or below down. This stand was likely saved from harvesting because of the long distance from the road and by the swamp. The stand can give us some insight into what the other two forest stands may have looked like.

Recommendation
As noted in Table 4 ( A + B ) of Lesson 2, we see that the white birch, red maple, and beech are likely overmature and are beginning to die. The red spruce, sugar maple, yellow birch, and eastern hemlock are reaching maturity. The site should be assessed for regeneration. If necessary, shelterwood cutting could be started.

 

Tree Species Abbreviations

SOFTWOODS
 
  
red spruce - rS
balsam fir
- bF
eastern hemlock
- eH
white spruce
- wS
black spruce
- bS
white pine
- wP
larch (tamarack)
- La
red pine
- rP
 
 
  
  
HARDWOODS
 
red maple
- rM
  
sugar maple
- sM
yellow birch
- yB
white birch
- wB
beech
- Be
aspen (poplar)
- As
red oak
- rO
white ash
- wA
pin cherry
- pC
grey birch
- gB
striped maple
- stM

 

Downloads

As the Home Study modules become available copies will be made available for download. At this time only the Introduction - Getting More from your Woodlot, Module 2 and 9 are available in French.

All modules are currently available in English and some in French Adobe Acrobat

Acrobate D'Adobe
Principles of Forest Stewardship Download
Introduction: Getting More From Your Woodlot English
Francais
Module 1: Introduction to Silviculture Download
Module 2: Harvesting Systems English
Francais
Module 3: Thinning for Value Download
Module 4: Woodlots and Wildlife Download
Module 5: Stand Establishment Download
Module 6: Chainsaw Use and Safety Download
Module 7: Woodlot Ecology Download
Module 8: Wood Utilization and Technology Download
Module 9: Woodlot Recreation English
Francais
Module 10A: Managing Woodlot Finances:Planning and Investment Guide Download
Module 10B: Introduction to Woodlot: Income Tax and Estate Planning Download
Module 11: Roads & Trails: Planning it Right from the Start Download
Module 12: Small Scale Harvesting Equipment Download
Module 13: Non Timber Forest Products: Growing Opportunities Download