Common Forestry Practices (TEXTBOOK)

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What is a site?

An area of ground on which a forest is, or will soon be, residing.

Why are site characteristics important? What characteristics?

The physical and biological characteristics of a site can be used to determine the types of forest it may support.

What is site preparation?

Making the site suitable for the establishment of a new forest (usually an even-aged forest).

What is forest establishment success often dependent on?

 The level of competition that the seedlings encounter and whether the seeds are in contact with mineral soil.

Which factors may cause variation in the desirable site preparation activities for a particular site?

Vary by vegetation type, ecosystem, and socioeconomic conditions. 

What are come common site preparation activities?

Burning, chopping, raking, plowing, and bedding.

What is burning as a site preparation activity?

Burning piles of debris is used to clear debris from a logged area.

What are chopping and crushing practices?

Practices used to break down larger residual materials to facilitate burning.

What is raking as a site preparation activity?

A bulldozer or skidder with a toothed blade penetrates and mixes the soil to disrupt existing root systems from the previous forest.

What is bedding as a site preparation activity?

The creation of long, linear planting mounds that reduce seedling mortality from waterlogged soils.

What is subsoiling/ripping as a site preparation activity? When is it used?

Sometimes used on soils where potential tree root growth can be restricted by soil compaction or because of a natural hardpan. 

What is aerial application of herbicide as a site preparation activity?

Helicopters or planes disperse herbicide to kill undesirable vegetation that may heavily compete with tree seedlings.

What two practices work great in combination for eliminating competitive vegetation from a site?

Combining aerial application of herbicide with controlled burns increases effectiveness beyond what either treatment alone could do to clear vegetation.

What are the drawbacks of extensive site preparation?

Soil compaction and topsoil removal.

What are the two ways that forest regeneration may occur?

Can proceed naturally or artificially with the assistance of seeds, seedlings, or coppice (stump sprouts).

What is forestation?

Refers to artificial methods of reforesting or restocking an area.

What is reforestation versus afforestation?

Reforestation involves establishing a new forest on an area of land that has recently supported a mature forest, whereas afforestation  refers to establishing a new forest on an area of land that has not recently supported a forest. 

What is the recent residency definition for a forest?

Defined as about 50 years. 

Compare the general use of reforestation activities versus afforestation activities.

Generally speaking, reforestation activities help maintain the forest area, while afforestation activities help increase the forest area. 

What are coppice shoots?

New growth (stems) arising from dormant or adventitious buds near the base or stump of a tree, where the previous tree was cut.

What are root suckers?

Root suckers arise from shallow or exposed root systems that have been wounded, perhaps within a short distance of the tree’s stump.

In what type of tree is coppicing frequently seen?

Hardwoods.

Coppicing and root suckers are both examples of….

Natural regeneration

What is artificial regeneration?

Artificial regeneration involves using seeds, seedlings, or rooted cuttings to establish a new forest.

How is seeding often done in artificial regeneration?

Seeding is often performed aerially by dropping out of planes or helicopters across recently harvested lands.

Pros and cons of seeding.

Seeding may increase the chances of successful reestablishment, but may also result in high density that requires thinning. Consumption of seeds by rodents, advanced plant competition, and seed availability limitations may all pose problems as well. 

What is an important stipulation of seeding?

Seeds should be collected from forested areas near the planting site or from an area with a compatible seed zone to maximize the probability of success.

Alternatives to seeding for artificial regeneration?

• Rooted cuttings

• Saplings

How are rooted cuttings used for artificial regeneration?

A developed shoot cut from a hedge or donor tree that is planted in soil to allow the development of a root system) may be transported to the area and planted. 

How are seedlings used for artificial regeneration?

Seedlings may also be lifted from nursery beds and transported to the area and planted. 

What are shelter belts?

 Afforested plantations of trees planted to shelter farmland and agricultural crops from wind, erosion, or serve as fuelwood or income in arid/semiarid environments. 

• Reduce wind velocities, reduce evaporation rate, increase soil moisture, and reduce extreme summer and winter temperatures. 

What are early tending practices?

Refer to activities that take place shortly after establishment of an even-aged forest to help reforestation. It can also refer to controlling the understory vegetation of uneven-aged forests. 

What are release activities?

Involve freeing desired young tree species from overstory competition, preventing the development of undesirable plant species, or removing brush, grasses, weeds, or other plant competition from the area around small developing trees.

What is weeding?

One type of early tending activities applied to regenerated forests to eliminate or suppress undesirable vegetation growing alongside the desired tree seedlings. 

How does early browsing of seedlings effect regeneration?

Early browsing of seedlings may open up pathways for disease or insect infestation, the development of multiple stems, increases susceptibility of trees to frost damaged, weakened branches.

How can early browsing be offset by early tending practices?

Protective devices, physical barriers, and chemicals on or around seedlings to increase growth rates and decrease mortality rates. 

What are precommercial thinnings?

Cuts made in dense, even-aged stands 3-20 years old where trees are not large enough to have sufficient commercial value to fund the practice. These precommercial thinnings are designed to remove trees of undesirable species and facilitate accelerated diameter growth, maintain desirable tree stocking levels, regulate tree species composition, and improve the form and quality of the remaining trees. 

What is a pro and a con of pre commercial thinnings for regeneration.

• Pro: Cut trees are generally left on the ground to enrich the soil and provide the surrounding trees with additional light, water, and nutrients to enhance growth. 

• Con: The downed woody material may temporarily increase risk of forest fires due to increased fuel load.

What is the purpose of pruning?

Aims to limit the number and size of knots in the bole of the tree so that higher-quality and value boards can be milled. They may also be pruned in urban areas for safety reasons.

What is pruning?

Involves the lower branches of trees being removed using pruning ladders and saws.

• The lower branches often die naturally and fall once the canopy fully forms, but this takes time and varies among tree species.

Low pruning versus high pruning

Brashing or low pruning refers to only pruning the tree branches that are within reach, which is the opposite of high pruning.

What is a thinning entry?

The age at which a thinning occurs

What is a thinning cycle?

The number of years between subsequent thinnings following the thinning entry.

What is thinning intensity defined by?

The combination of the frequency of thinnings and the amount of removals each time.

What is a thinning regime?

Represents the type, degree, and frequency of thinning practices that are employed in a forest. 

What are selective thinnings?

Generally involve the removal of inferior trees to promote continued development in superior trees, but it can also involve removal os superior trees to promote the development of smaller trees into merchantable product size classes by increasing growing space.

What is thinning from above? What else might this be called?

Trees from the dominant, codominnant, and suppressed tree classes. When this is done to improve long-term improvement and development, it is called high thinning.

What is thinning from below?

Involves the trees from the subdominant and suppressed classes being removed.

What does it mean to thin proportional to the diameter distribution?

Requires that an equal number of trees are removed from all diameter size classes. 

What is a final harvest?

A clearcut practice that involves the removal of virtually all trees in an area in one continuous harvesting operation.

What is alternative clear-strip cutting?

A final harvest strategy of clearcutting where uncut strips are left between harvests to promote the regeneration from seed of mature trees.

What is the rotation age?

 The average age of trees at the time of the final harvest. 

What are group selection harvests?

Practices that open the canopy through small groups of harvests that create gaps for regeneration to occur. Used to mitigate the aesthetic issues related to clearcutting.

What is a return interval?

Defines the number of years before the next set of patches is removed when conducting a group selection harvesting operation.

What is a seed tree?

One that is left standing on purpose during a final harvest to serve as a source of seeds for natural regeneration of a new, even-aged forest.

What are seed-tree harvest practices?

Practices that involve the removal of all trees (or merchantable trees) in a forest with the exception of a collection of seed trees. 

What are shelterwood harvest practices?

When the new, even-aged forest is naturally regenerated and established using seeds or trees from the previous forest. This is similar to the seed tree harvest strategy except that the mature overstory trees remain and provide protection to the seedlings as they become established. 

What are partial selection harvests?

Involve removing a scattered arrangement of the oldest and largest trees, enhancing the ability of smaller trees to grow into canopy caps while enhancing the economic value as well. May promote the regeneration of shade-tolerant species, whereas the group selection practice generally favors the regeneration of shade-intolerant species. This continuous establishment of naturally regenerated trees maintains and encourages the uneven-aged character of the forest.

Partial selection harvests are suggested as a means of….

Promoting and maintaining late-successional and old-growth characteristics of shade-tolerant sugar maple and American beech.

What are selective harvest practices?

Involve removal of trees according to age, quality, size, or value with little regard for the remaining or residual forest character (high grading). Generally not recommended because sustainability is generally ignored. 

What is a salvation harvest?

Involves the removal of dead, dying, or deteriorating trees from a forest before the value of the wood deteriorates below the extraction costs. May also be used to remove trees with no economic value to promote healthy regenerated forests.

What is a sanitation harvest?

Involves the removal of trees with the intent of improving the overall health of the forest. The primary goal would be to stop, reduce, or prevent the spread of damage imposed by insects or diseases. 

What is prescribed burning?

The intentional, controlled application of fire to a forest to accomplish land management goals. Usually surface fires that burns under the canopy of an established stand of live trees. 

What is the forest fuel load?

Consists of the live and dead fuels across a landscape, and is a key determinant of how severe a wildfire may be. 

What are the classes of forest fuel load?

• Ground fuels: Located either below the soil surface or within the organic layer and include duff, organic soils, roots, stumps, and buried logs.

• Surface fuels: Forest litter, branches, logs, and other dead vegetation lying on the surface of the ground.

• Ladder fuels: The live and dead branches that provide a path for the fires to reach the crowns of trees. 

What is agroforestry?

Sustainable management system for land that increases overall production, combines agricultural crops, tree crops, and forest plants and/or animals simultaneously or sequentially and applies management practices compatible with cultural patterns of the local population.

What are silvopastoral systems?

Agroforestry systems that combine tree growing w/ the production of livestock. Typically include pasture systems with trees that are widely spaced or planted in clusters throughout.

What is alley cropping?

Specific agroforestry practice in which trees or shrubs and agricultural crops are grown in alternate rows. Trees are commonly pruned to limit the shading of the crop. Can also help nutrient cycling and erosion control.

What are windbreaks?

Agroforestry method where groups of trees that are planted in rows to protect production of crops and serve as shelters for livestock.

What is clonal forestry?

Genetic improvement is promising in that faster-growing trees can be used to mitigate excess atmospheric Co2. Sexual reproduction is avoided to only produce the exact desired trees, often using somatic embryogenesis (process of creating embryos from cells of plants other than gametes) or through the development of rooted cuttings.