Introduction:

Annual variation in growth ring characteristics has an impact on productivity and wood quality.

Objective:

To evaluate radial growth in two Pinus patula Schltdl. & Cham. plantations of different ages and thinning intensity, as well as its relationship to interannual variation in temperature and rainfall.

Materials and methods:

Growth ring characteristics were analyzed in wood samples from 13- and 23-year-old plantations, subjected to three thinning intensities (null, light and moderate). The characteristics were related to climate data during the years of ring formation using Pearson's correlation analysis.

Results and discussion:

In the 1995 plantation, ring characteristics did not show significant differences (P > 0.10) between plots with and without thinning, due to excessive competition and crown recession. Ring width, and early and latewood width, was significantly associated (P < 0.10; r ≥ 0.40) with average minimum temperature. In the 2005 plantation, trees from the thinned plots showed greater ring width, earlywood width and basal area increment than those from the unthinned plot. In this plantation only latewood width was positively associated (P < 0.10; r = 0.69) with temperature and negatively (P < 0.10; r = -0.61) with annual rainfall.

Conclusion:

Growing space and competition intensity mainly affected ring and earlywood width. Environmental factors influence ring characteristics.