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Seed dormancy[ edit ] Seed dormancy is a complex phenomenon and is not always consistent within species.

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Under natural days in Florida, with the short local photoperiod, white spruce was severely dwarfed and had a low rate of survival. Spacing[ edit ] Over-crowded regeneration tends to stagnate. Cold stratification[ edit ] Cold stratification is the term applied to the storing of seeds in and, strictly, in layers with a moist medium, often peat or sand, with a view to maintaining viability and overcoming dormancy.

The term "free growing" is applied in some jurisdictions.

Silviculture - definition of silviculture by The Free Dictionary

Scarification, for instance, not only covers a wide range of operations that scarify, but also any given way of scarifying can have significantly different results depending on site silvicultura significado yahoo dating at the time of treatment. Planting can involve using seedlings from a nurseryun rooted cuttings, or seeds.

Seed ripeness[ edit ] Seed maturity cannot be predicted accurately from cone flotation, cone moisture content, cone specific gravity; but the province of B. Wings of white and Norway spruce seed can be removed by dampening the seed slightly before it is run through a fanning mill for the last time.

Encouraged by Russian success in using ultrasonic waves to improve the germinative energy and percentage germination of seeds of agricultural crops, Timonin [48] demonstrated benefits to white spruce germination after exposure of seeds to 1, 2, or 4 minutes of ultrasound generated by an M.

The oldest interior spruce espacement trial in British Columbia was established in near Houston in the Prince Rupert Forest Region. Spacing is a thinning of natural regenerationin which all trees other than those selected for retention at fixed intervals are cut. By altering stand densityforesters can age for pre kg admission in bangalore dating the growth, quality, and health of silvicultura significado yahoo dating trees.

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Hills' [40] site regions and provincial resource district boundaries, but Ontario's seed zones are now based on homogeneous climatic regions developed with the Ontario Climate Model. Twenty years after spacing to 2. The treatment can be of the crop itself e.

When natural regeneration or artificial seeding has resulted in dense, overstocked young stands, natural thinning will in most cases eventually reduce stocking to more silviculturally desirable levels.

February Artificial regeneration[ edit ] With a view to reducing the time needed to produce planting stock, experiments were carried out with white spruce and three other coniferous species from Wisconsin seed in the longer, frost-free growing season in Floridavs. It is well established that the regeneration and growth potential of understorey conifers in mixedwood stands is correlated to the density of competing hardwoods.

Many promising plantations have failed through lack of tending. Crown width showed a gradual increase with spacing for all 3 conifers.

Perhaps the most direct evaluation of the effect of competition on plantation establishment is provided by an effective herbicide treatment. After two growing seasons, white spruce under long days in Florida were about the same as those in Wisconsin, but twice as tall as plants under natural Wisconsin photoperiods.

Clear knot-free lumber has a higher value. The slowness of juvenile growth and of crown closure delay the response to intra-competition. Growth performance is certainly influenced by site conditions and thus by the kind and degree of site preparation in relation to the nature of the site. Burning site preparation has enhanced spruce seedling growth, [] but it must be supposed that burning could be detrimental if the nutrient capital is significantly depleted.

They further questioned the quality of the 2-year-old seed even though high germination occurred in the samples that were not stratified. Generally, one or two times precommercial thinning is done to facilitate the growth of the tree The yield of merchantable wood can be greatly increased and the rotation shortened by precommercial thinning.

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Various competition indices have been developed, e. The movement of general-collection seed and stock across seed zone boundaries is prohibited, but the use of stand-collection seed and stock in another seed zone is acceptable when the Ontario Climate Model shows that the planting site and place of seed origin are climatically similar.

Tending[ edit ] Tending is the term applied to pre-harvest silvicultural treatment of forest crop trees at any stage after initial planting or seeding.

Most commonly, the method of managing seed and stock deployment is through a system of defined seed zones, within which seed and stock can be moved without risk of climatic maladaptation. Dry seed may be rubbed gently through a sieve that has a mesh through which only seed without wings can pass.

The 12 seed zones for white spruce in Quebec are based mainly on ecological regions, with a few modifications for administrative convenience. Early stand development after harvesting or other disturbance undoubtedly varies greatly among sites, each of which has its own peculiar characteristics. The fundamental genetic consideration in artificial regeneration is that seed and planting stock must be adapted to the planting environment.

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Stand Conversion[ edit ] The term stand conversion refers to a change from one silvicultural system to another and includes species conversion, i. Establishment density targets or regeneration standards have commonly been based on traditional practice, with the implicit aim of getting the stand quickly to the free-to-grow stage.

Scarification is defined [2] as "Loosening the top soil of open areas, or breaking up the forest floor, in preparation for regenerating by direct seeding or natural seedfall", but the term is often misapplied to practices that include scalping, screefing, and blading, which pare off low and surface vegetation, together with most off its roots to expose a weed-free surface, generally in preparation for sowing or planting thereon.

It is important to avoid the assumption that site preparation of a particular designation will have a particular silvicultural outcome. Methods for spacing may be: Artificial extension of the photoperiod in the northern Lake States greatly increased height increment of white and black spruces in the second growing season.