Control of hardwoods is vitally important in the establishment of Douglas-fir seedlings on Pacific Northwest forest lands. In reducing the competition of these brushy species, herbicides have become nearly an indispensable tool. However, with the increasing awareness of the importance of a clean environment, it has become apparent that the safe use of these chemicals requires a knowledge of the...

A brief overview of the structure of mannans in plant cell walls and other organisms is presented. In particular, mannans, galactomannans and glucomannans in seed endosperm and vegetative tissues such as bulbs and tubers, galactoglucomannans (GGMs) in primary cell walls, and glucomannans and GGMs in secondary walls of hardwoods and softwoods are covered. Possible roles of mannans in primary pla...

speaking, do not have roots, rather they form mycorrhiza. There are seven principle types of mycorrhiza. The two most important mycorrhizas are the endomycorrhiza and ectomycorrhiza. Endomycorrhiza typically colonize herbaceous plants, shrubs, many ornamental, fruit and nut trees, vegetables and agronomic crops, and turf grasses. More than 85% of higher plants form endomycorrhizal associations....

This paper describes changes that have occurred in the silviculture of southern bottomland hardwood forests over the past 25 years, particularly in terms of modifications to existing silvicultural practices, abandonment of unsuitable practices, and development of new practices. Changes in the focus and objectives of hardwood silviculture and the emergence of new concerns to hardwood silvicultur...

pact B horizon, high in colloid. There is an obvious relationship between rate of height growth of trees and recognizable quantitative group combinations of factors, such as are summarized, for instance, in a specific soil type of specific slope and exposure. There is even more evident relationship between rate of height growth and specific soil profile characteristics. It has been possible to ...