Morphological and physiological responses of hardwood trees to plantation thinningThis article is part of a larger document. View the larger document here.
A mixed hardwood plantation in Indiana was selected as a pilot study to investigate physiological and morphological responses of northern red oak (Quercus rubra L.), white oak (Q. alba L.), and black walnut (Juglans nigra L.) to thinning. Trends from the first growing season after harvest suggest average daily soil water content and soil temperature were higher in thinned plots when compared to control plots. All three species showed higher net photosynthesis rates in thinned plots. Increased production of photosynthate allowed trees in thinned plots to allocate more resources toward secondary growth as shown by increased diameter growth. Thinning, however, did not appear to increase soil nutrients, leaf water potential, crown surface area or height growth in a single growing season. Results suggest some variables responded to thinning during the first growing season after harvest, while others did not. Morphological parameters will be monitored to determine if current trends continue in subsequent years.