Growth After Thinning a 35-Year-Old Natural Stand to Different Loblolly Pine and211 Hardwood Basal Areas

摘要

Growth was monitored for 4 yr in a thinned stand in southern Arkansas with three211u001epine basal areas (70, 85, and 100 ft2/ac) and three hardwood basal areas (0, 15, 211u001eand 30 ft2/ac); pretreatment basal averaged 119 and 33ft2/ac, for pines and 211u001ehardwoods, respectively. Treatments were arranged in a 3 x 3 factorial randomized 211u001ecomplete block design with three replicates, yielding 27 permanent 0.20 ac plots. 211u001eGrowth variables were regressed with residual pine and hardwod basal areas. Pine 211u001ebasal area and volume growth increased with the pine stocking level after 211u001ethinning and decreased with the level of retained hardwoods. For basal areau and 211u001emerchantable volume, hardwood growth largely compensated for losses in the pine 211u001ecomponent, and thus, hardwood retention had little net effect on the total growth 211u001eof the stand. The greatest impact of hardwood retention was on the stand's 211u001esawtimber-growth, because hardwoods did not contribute to this product class. 211u001eEach I ft2/ac of retained hardwood basal area reduced pine sawtimber growth by 6 211u001eto IO bd ft Doyle/ac/yr, depending on the pine stocking. Because large 211u001edifferences existed in the value of timber-products, retaining 15 and 30ft2/ac of 211u001ehardwoods reduced the value of timber production by 13 and 24%, respectively, at 211u001e4 yr-after thinning.