TY - JOUR

T1 - Variability among Sites and Climate Models Contribute to Uncertain Spruce Growth Projections in Denmark

AU - Huang, Weiwei

AU - Fonti, Patrick

AU - Ræbild, Anders

AU - Larsen, Jørgen Bo

AU - Wellendorf, Hubert

AU - Hansen, Jon Kehlet

PY - 2021

Y1 - 2021

N2 - Projecting trees species growth into future climate is subject to large uncertainties and it is of importance to quantify the different sources (e.g., site, climate model) to prioritize research efforts. This study quantifies and compares sites and climate model-induced uncertainties in projected Norway spruce growth from Denmark. We analyzed tree-rings from 340 Norway spruce treessampled in 14 planted stands (1. Plantation; period 1950–1987) and additionally 36 trees from six trials in a common garden experiment (2. Common garden; period 1972–2012). Growth-climate correlations were estimated and multiple linear and nonlinear regression models relating growth with climate were tested. Tree growth was projected up to 2100 applying multiple linear or quadraticregression models based on the 15 Atmosphere-Ocean General Circulation Models (AOGCMs) of the Coupled Model Inter-comparison Project Phase 5 (CMIP5). The climate-growth models showed that summer drought and warm previous-year late-summer and early-autumn constrain growth. In somestands, warm springs affected growth positively. The projections of growth under future climates on average showed from no to slightly negative changes in growth compared to present growth rates. However, projections showed a very large variation, ranging from highly positive to highly negative growth changes. The uncertainties due to variation in site responses and in climate modelswere substantial. A lesser degree of uncertainty was related to the emission scenarios. Even though our projections on average suggest that Norway spruce may experience a growth reduction in the future, the tremendous variation in growth predictions due to differences between stands and climate models calls for further research and caution when projections are interpreted. These results also suggest that forest managers in general should avoid the use of Norway spruce on exposed and drought prone sites and as an additional resilience measure primarily use it in mixtures with other more climate tolerant species.

AB - Projecting trees species growth into future climate is subject to large uncertainties and it is of importance to quantify the different sources (e.g., site, climate model) to prioritize research efforts. This study quantifies and compares sites and climate model-induced uncertainties in projected Norway spruce growth from Denmark. We analyzed tree-rings from 340 Norway spruce treessampled in 14 planted stands (1. Plantation; period 1950–1987) and additionally 36 trees from six trials in a common garden experiment (2. Common garden; period 1972–2012). Growth-climate correlations were estimated and multiple linear and nonlinear regression models relating growth with climate were tested. Tree growth was projected up to 2100 applying multiple linear or quadraticregression models based on the 15 Atmosphere-Ocean General Circulation Models (AOGCMs) of the Coupled Model Inter-comparison Project Phase 5 (CMIP5). The climate-growth models showed that summer drought and warm previous-year late-summer and early-autumn constrain growth. In somestands, warm springs affected growth positively. The projections of growth under future climates on average showed from no to slightly negative changes in growth compared to present growth rates. However, projections showed a very large variation, ranging from highly positive to highly negative growth changes. The uncertainties due to variation in site responses and in climate modelswere substantial. A lesser degree of uncertainty was related to the emission scenarios. Even though our projections on average suggest that Norway spruce may experience a growth reduction in the future, the tremendous variation in growth predictions due to differences between stands and climate models calls for further research and caution when projections are interpreted. These results also suggest that forest managers in general should avoid the use of Norway spruce on exposed and drought prone sites and as an additional resilience measure primarily use it in mixtures with other more climate tolerant species.

U2 - 10.3390/f12010036

DO - 10.3390/f12010036

M3 - Journal article

VL - 12

JO - Forests

JF - Forests

SN - 1999-4907

IS - 1

M1 - 36

ER -