This paper presents equations developed to predict the height to live crown base of six species in the central western Willamette Valley of Oregon. Weighted nonlinear regression was used to fit a separate logistic equation for each species. The predictor variables are total tree height, crown competition factor in trees...
Equations for predicting tree height as a function of diameter
outside bark at breast height are presented for 16 tree species
from the central western Willamette Valley of Oregon. Foresters
can use these "height-diameter" equations to avoid the time consuming
task of measuring heights of all individual trees in an...
Equations are presented for predicting height to crown base (or bole ratio) for fourteen species of trees common to the mixed-conifer zone of southwest Oregon. Nonlinear regression was used to fit a weighted logistic function for each species. The independent variables include height, crown competition factor in larger trees, stand...
Equations for predicting total height as a function of diameter at breast height are presented for 17 tree species from southwest Oregon. Because basal area and site index often influence tree height, additional equations are presented which may include either or both of these as independent variables. Equation coefficients were...
Perennial woody plants have a complex annual cycle keyed to the environment. Temperate plants have an annual dormant period commonly broken by exposure to low temperatures, although daily photoperiods of 16 hours or longer may partially substitute for the chilling. Shoot growth in the spring is normally stimulated by rising...
Logging on skid trails restricted to 10 percent or less of the harvested stand can reduce the area of compacted soil by at least two-thirds, In a comparative study, productivity of Douglas-fir logs per hour was just as great In an area with designated trails as In an adjacent area...
Black cottonwood (Populus trichocarpa Torr. & Gray) cuttings were collected from five Oregon provenances along a north-south gradient. Cuttings from each provenance were grown for 1 year at two locations, one on the Willamette Valley floor and the other on the Valley margin. Survival at both locations was poor. Stem...
The effects of artificial shading and aspect on the performance of 1-0 container-grown Douglas-fir seedlings were evaluated 1 year after outplanting on four different aspects in southwest Oregon. The test areas, all characterized by steep slopes and shallow, skeletal soils with a surface mantle of loose rock and logging slash,...