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Growth & Development of Older Plantations in Northwestern Pennsylvania

出版	Northeastern Forest Experiment Station, Forest Service, U.S. Department of Agriculture, 1968
URL	http://books.google.com.hk/books?id=lSxY0AEACAAJ&hl=&source=gbs_api

註釋S2By re-examining some of the oldest plantations in northwestern Pennsylvania, we have gained new insights into the survival and growth of these planted trees. And we have changed some of our ideas about which species should be favored for planting in this area. In northwestern Pennsylvania, thanks to a previous study by J.E. Hetzel, we have records on enough plantations now close to 50 years old so we can get a good idea of how valuable a number of species are for reforestation, particularly on old fields. Hetzel in 1939 had located an examined more than 40 plantations in this area, most of which were then between 18 and 27 years old. Besides his published report, we have his study files, which enabled us to relocate the plantations. His records also contained information about planting each species in each plantation. Having this excellent data, we decided to revisit and re-measure as many of these plantations as possible. Our purpose was to evaluate the species, mainly in terms of volume production and to compare the results in a general wary with those Hetzel got in 1939.S3.