Soil solution, foliar concentrations and tree growth response to 8 years of ammonium-nitrate additions in two boreal forests of Quebec, Canada

2019 ◽  
Vol 437 ◽  
pp. 263-271
Author(s):  
Daniel Houle ◽  
Jean-David Moore
2007 ◽  
Vol 37 (6) ◽  
pp. 1093-1105 ◽  
Author(s):  
Philip Smethurst ◽  
Andrew Knowles ◽  
Keith Churchill ◽  
Ann Wilkinson ◽  
Arthur Lyons

We required an improved understanding of K deficiency and diagnosis in Pinus radiata D. Don (radiata pine). A rapid growth response to K fertilization (100 kg·ha–1) in the presence of weed control confirmed K deficiency in a 2-year-old stand. Tree growth did not respond to N fertilization, and weed control alone appeared insufficient to maximize tree growth. Temporal patterns in visual symptoms of K deficiency suggested they were worst at the end of a drought, and improved after several months of above-average rainfall that coincided with an increase in soil temperature. Soil chemistry generally responded predictably to fertilization, but K fertilization increased soil solution Ca and Mg concentrations without changing exchangeable concentrations. With weed control, a doubling of stem growth response to K fertilizer was associated with a 270% increase in soil solution K (natural variation amongst control plots), 51% increase in exchangeable K, and 39% increase in foliar K. Relationships between seedling growth and hydroponic concentrations of K were consistent with the incidence of K deficiency in the field; predicting these deficiencies using soil exchangeable concentrations was less clear. This study advances the interpretation of soil and foliar chemistry in relation to K and Mg deficiency in P. radiata.


2020 ◽  
Vol 108 (6) ◽  
pp. 2198-2211
Author(s):  
Tommaso Jucker ◽  
Julia Koricheva ◽  
Leena Finér ◽  
Olivier Bouriaud ◽  
Giovanni Iacopetti ◽  
...  

Forests ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 228 ◽  
Author(s):  
Hongliang Gu ◽  
Jian Wang ◽  
Lijuan Ma ◽  
Zhiyuan Shang ◽  
Qipeng Zhang

Dendroclimatology and dendroecology have entered mainstream dendrochronology research in subtropical and tropical areas. Our study focused on the use of the chronology series of Masson pine (Pinus massoniana Lamb.), the most widely distributed tree species in the subtropical wet monsoon climate regions in China, to understand the tree growth response to ecological and hydroclimatic variability. The boosted regression trees (BRT) model, a nonlinear machine learning method, was used to explore the complex relationship between tree-ring growth and climate factors on a larger spatial scale. The common pattern of an asymptotic growth response to the climate indicated that the climate-growth relationship may be linear until a certain threshold. Once beyond this threshold, tree growth will be insensitive to some climate factors, after which a nonlinear relationship may occur. Spring and autumn climate factors are important controls of tree growth in most study areas. General circulation model (GCM) projections of future climates suggest that warming climates, especially temperatures in excess of those of the optimum growth threshold (as estimated by BRT), will be particularly threatening to the adaptation of Masson pine.


Author(s):  
Jan Altman ◽  
Kerstin Treydte ◽  
Vit Pejcha ◽  
Tomas Cerny ◽  
Petr Petrik ◽  
...  

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