Growth of slash pine natural regeneration in strip-clear cutting with different width and orientation, in Northeast Argentina

CABRELLI, DANIEL; REBOTTARO, SILVIA; WINCKLER, CLAUDIO; REZZANO, CARLOS; TORRES, ALBERTO; AMOROSO, MARIANO

Knoxville, Tennessee, USA

Conferencia; Silvicultural Conference USDA Forest Service Southeast Research Station; 2001

U.S. Department of Agriculture, Forest Service, Southeast Research Station

Slash pine (Pinus elliottii Engelm. var elliottii) is exotic species intensively used in forest crops in Argentina. In many crop areas natural regeneration was reported, but studies about dynamics of this process in our country are recent. This work describes the seedling growth of slash pine natural regeneration in silvicultural gaps. The study was carried out in the Yuquerí Agricultural Experiment Station (31°22’S lat, 58°07’W long, 154 ft a.s.l.) Entre Ríos, Argentina. In 17-19 years-old slash pine stands strip-clear cutting were effectuated. Three strips (40, 60 and 80 feet) and two cardinal orientations (E-W and N-S) were established. Permanent plots were installed. Groundline diameter (g.l.d.) and total height (h) were measured every year. Solar radiation in the strips was estimated for hemispherical photography. The present results are over two years. An asymptotic relationship was detected between growth and strip width. Silvicultural gaps with wide strip/height of tree inter-strips ratio (w/hi) higher than 1 not produced increase in the growth. The effect of cardinal orientation on seedling growth only was important when the w/hi ratio was lower than 0.6. Solar radiation inside strips had an important role in the growth of the natural regeneration. The h/g.l.d. ratio in seedlings decreased when the width increased. In E-W orientation the h/g.l.d. ratio was smaller than N-S orientation.