Effects of thinning intensity on radial growth patterns and temperature sensitivity in Pinus canariensis afforestations on Tenerife Island, Spain

Abstract

The suitability of thinning to prevent forest growth decline from global warming has been 25 scarcely tested in the Macaronesian Canary pine (Pinus canariensis Sweet ex Spreng.). We used tree-ring series from dominant, codominant, and overtopped trees to study the 27 effects of thinning intensity on basal area increments (BAI) and climate sensitivity on windward 28 (wet) and leeward (dry) slopes on Tenerife, Canary Islands. Three replicated blocks of control, 29 light thinning, and heavy thinning stands were set on each slope in 1988, and cores were 30 extracted in 2007. Heavy thinning induced growth release and increased BAI, mainly on dominant and 32 codominant trees, whereas light thinning effects were negligible; their impacts were more intense 33 on windward. Temperature sensitivity was hardly affected by thinning on leeward, where climate 34 control was stronger. On windward, thinning enhanced the influence of summer temperatures. 35 Upper crown classes were overall more sensitive, but overtopped trees responded better in 36 summer. Thinning intensity and aspect greatly influence growth on Canary pine afforestations, but 38 individual responses are highly dependent on crown classes. In addition, thinning may be less 39 effective to modify growth conditions on leeward slopes, at least if it is not intense.