Presentation on theme: "FORESTRY: ENVIROTHON About 30% of the world is forested today, but the ratio between forest and population varies immensely. More than one half of the."— Presentation transcript:
FORESTRY: ENVIROTHON About 30% of the world is forested today, but the ratio between forest and population varies immensely. More than one half of the world's softwood timber (the major forest product) comes from North America and Europe—an area with only a fourth of the world's population. The forested area of the United States has shrunk in 300 years from about one half to one third of the total land acreage. The United States and Canada share 16% of the world's forests; the former Soviet Union contains 21%, Africa has 20%, and Latin American has 24%.
FORESTS: ASSESSING THE RESOURCE Depending on “what you want” from a forest will determine what you will and won’t do to it…… Minimally even if you were to preserve the forest you have to know what’s there. That inventory could be the trees (and all other life and non-life there: smaller plants, animals, bacteria, fungi, soils, hydrology, etc.)
WHAT SPECIES? Measuring the diversity or species composition of your forest is almost always a basic and prime concern. One way to identify trees particularly if the species are new to you is to use a KEY. Some items that appear in keys that are useful to know are: Leaf shapeBranching pattern Leaf type
WHAT SPECIES? Other useful characteristics to help identify trees are: Bark characteristics Fruits Flowers
WHAT SPECIES? Tree form Smell (leaves, bark) Leaf tips Leaf bases Site Buds, twigs ETC…….
Tree diameter and heights using Biltmore stick/Merritt hypsometer
TREE DIAMETER (DBH): D-tape measure at 4.5 ft from ground….
TREE HEIGHT (TOTAL): Suunto Clinometer Two measurements: -One at ground level -The other the very top of the tree HEIGHT=TOP MEASUREMENT – BOTTOM MEASUREMENT (BE CAREFUL: THERE ARE + and – READINGS YOU CAN GET!)
TREE AGE (at breast height): Increment corer
TREE AGE (at breast height) CONT’D: We bore the tree at breast height 4.5 feet from the ground….
You can bring the cores back to the lab, mount and sand them and do some DENDROCHRONOLOGY (study of tree rings).. TREE AGE (at breast height) CONT’D:
SILVICULTURE “the art and science of controlling the establishment, growth, composition, health, and quality of forests and woodlands to meet the diverse needs and values of landowners and society on a sustainable basis through the application of silvics”
SILVICS: ….the life history and general characteristics of forest trees and stands, with particular reference to environmental factors….
SILVICULTURE CONTROLS: Stand composition Stand density Restock underproductive areas Protection and salvage Control rotation length Facilitate the harvest, management, and use of the forest Protection of the site and indirect benefits
SILVICULTURAL SYSTEMS REGENERATION SYSTEMS Even-aged systems Clearcut systems Coppice systems Seed tree systems Shelterwood systems Uneven-aged systems Uneven-aged systems Group or Individual Selection systemselection systems CAN BE DIVIDED INTO THREE BROAD GROUPS: INTERMEDIATE CUTS Thinnings, cleanings SALVAGE/PROTECTION
Clearcut -usually INTOLERANT trees regenerated -create or promote even- aged stands -best with light seeded spp. -trees are overmature BE CAREFUL: -Can promote shrubs -can overexpose sensitive sites -slash can impair regeneration. -erosion on steep slopes
CLEARCUTS In strips….. or patches: Jack pine clearcut in Manitoba to mimic natural fire pattern
Coppice You are ASEXUALLY reproducing the forest: stump sprouts
Seed Tree The trees you leave as seed sources should represent the species you want and are the ‘best’ there…. What are the dangers to this process? Shortleaf seed tree (15 per acre)
SHELTERWOOD Preparatory cuts These may be one or several light cuts to improve the vigor and wind firmness of potential leave-trees to prepare for the next cuttings. Establishment, regeneration or seeding cut Establishment, regeneration or seeding cut This cutting, which may be the first cutting in some unmanaged stands, is to provide growing space for establishing regeneration while maintaining shelter for developing seedlings. Trees chosen to be retained after this cut should be vigorous and wind firm. Overstory removal cut(s) Once regeneration is established and stocking is acceptable, removal of the sheltering overstory is a common option. Alternatively, all or some of the sheltering residual overstory can be permanently or temporarily reserved from future cutting to satisfy management objectives.
SHELTERWOOD Shelterwood on Douglas fir in West (note slope of land)
SELECTION single tree Usually this and group are for TOLERANT trees and uneven-aged stand
SELECTION single tree Single tree selection : red spruce, hemlock, and balsam fir
SELECTION group Group selection: old growth spruce fir forest
INTERMEDIATE CUTS Treatment of stand during part of the rotation not included in regeneration period…. Intermediate cuts are used for: -improve existing stand -regulate growth -provision for early financial returns If regulate growth then called thinnings If regulate species composition: young stands: release cuttings old stands: improvement cuts If take branches off: pruning
INTERMEDIATE CUTS Many types of thinnings: Low (German) Crown (French) Selection Geometric Free
Low Thin Trees are removed from the lower crown classes Mimics natural mortality You can work in a range of Thinnings: A-B thin without risk of reducing wood production C-D stimulate growth of remaining trees (not just salvage)
CROWN THIN Remove trees in middle and upper crown classes Most trees cut are Codominant but can take out interfering Intermediates or Dominants Crown thinning favors nearly the same trees as Low thins but removes a few strong competitors rather than eliminate the weak (As Low thin does) Crown thin is more flexible but demands greater expertise…
SELECTION THIN -Dominant trees are removed to stimulate lower crown classes -Vigorous trees favored in Crown and Low are the very ones likely to be cut here -Be careful: limited use, could become High grading!
MECHANICAL THIN Aspen stand in which 5 meter wide strips are removed to thin…
PRUNING Very expensive and intensive BUT in certain circumstances you could get more money for the wood (no knots)
RELEASE CUTS/TREATMENT Done when stand is young to remove species not desired….. Pine stand above – releasing pines by using brush saw on undesirable species- the final result is the bottom picture
IMPROVEMENT CUTS BEFORE (LEFT) and AFTER (RIGHT) of HARDWOOD STAND In Mississippi- get rid of poorly formed species or undesirable species and shrubs…