Growth and Development of Pinegrass in Interior British Columbia

Abstract

Pinegrass (Calamagrostis rubescens Buckl.) is an important source of forage on forested and clearcut ranges in interior British Columbia. The vegetative growth and development of this infrequently flowering grass was documented. This information is required to improve our understanding of pinegrass grazing resistance and in turn, of its grazing management. Numbers of tillers m-2 and number of leaves per tiller were counted at intervals during the growing seasons of 1978 and 1979. Leaf blade area was measured at intervals during 1978 and 1979. Tiller height was recorded during 1978, 1979, and 1982, while shoot weight was recorded at intervals during 1982. Pinegrass had up to 4 leaves per tiller, but on average only 3.2 leaves were present by the time growth ceased in July. Total leaf blade area was reached in July, and is largely comprised of 2 leaves. Total leaf blade area (y) was predicted from tiller height (x):y = 0.39375 + 0.051604x + 0.00419223x^2 (R2=0.97). A large proportion of leaf blade area was dead by the end of July. Tiller weight reached a maximum in July; it increased during May to July owing to an increase in number of leaves, leaf area, and specific weight of leaves. Growth analysis indicated that net assimilation rate (NAR), and relative growth rate (RGR) were high in mid-May and then gradually decreased to zero in July. NAR and RGR of pinegrass appeared typical for C3 plants.