. Estimating productivity on sites with a low stocking capacity. Forests and forestry Mensuration; Forest site quality. Figure 4.—It is reasonable to assume that this creek bed is nonstockable. Learning to recognize sites that grow trees but are limited in stocking capacity is a complex problem. If we accept the premise that undisturbed stands tend to- ward equilibrium (Franz 1967), we can seek out such stands and compare their basal areas with those predicted by a normal yield table for the same stage of develop- ment. Those stands with less than "normal" stocking (including recent
. Estimating productivity on sites with a low stocking capacity. Forests and forestry Mensuration; Forest site quality. Figure 4.—It is reasonable to assume that this creek bed is nonstockable. Learning to recognize sites that grow trees but are limited in stocking capacity is a complex problem. If we accept the premise that undisturbed stands tend to- ward equilibrium (Franz 1967), we can seek out such stands and compare their basal areas with those predicted by a normal yield table for the same stage of develop- ment. Those stands with less than "normal" stocking (including recent mortality) can be assumed to have a stocking restriction. By measuring such stands, we could build a new "normal yield table" for sites with restricted stocking capacity. But how can we recognize restricted stocking capacity when disturbance has removed part or all of the tree cover? One way would be to study the effect on forest stocking of all the various physical factors which affect the environment: soil, microclimate, available moisture, slope, aspect, etc. Such an approach seems time consuming for an ecologist and probably hopeless for the average inventory crew. Even detailed soil infor- mation, although prospectively highly useful, is not easy to gather in most inventory situations. Fortunately, the plants growing on a site offer an important alternate source of information. Plants or plant commu- nities have often been used as indicators of environmental factors present, particu- larly those which are critical to plant growth on a particular location—e. g., moisture, temperature, fertility, etc. (Daubenmire and Daubenmire 1968, Dyrness and Youngberg 1966, Griffin 1967, Poulton 1970, Waring 1969, Youngberg and Dahms 1970). If plant communities representing various levels of forest productivity can be identified, then sepa- rate yield tables can be developed for each community, or in place of this, discount factors computed for existing yield tables. A PROC
Size: 1505px × 1661px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookcollectionameri, bookcollectionbiodiversity
