Oak decline induced by mistletoe, competition and climate change: a case study from central Europe.

Autor:	Doležal, Jiří, 1975 červenec 22.-
Další autoři:	Lehečková, E. Sohar, K. Altman, Jan, 1985-
Jazyk:	angličtina
Předmět:	botanika botany články journal articles conditional interference trees dendrometres moving response function growth-climate relationships intra-annual variation Loranthus europaeus Quercus robur stem contraction tree-eater relations
Druh dokumentu:	Non-fiction
ISSN:	0032-7786
Abstrakt:	Abstract: a1_It is predicted that rising temperatures and extreme summer droughts will adversely affect the growth of pedunculate oak (Quercus robur) and contribute to local population decline. Furthermore, such oaks may become prone to infestation with mistletoe (Loranthus europaeus) and competition from neighbouring trees. We tested these predictions in the warm, south-eastern part of the Czech Republic, a drought-prone area where oaks die prematurely. We compared the radial growth patterns of eight categories of oaks differing in age (younger or older than 60 years), presence of neighbouring trees (solitary versus grouped) and infestation with mistletoe (infested versus healthy), and their responses to variation in both annual and intra-annual temperature (T) and precipitation (P). We analysed long-term data from tree rings and detailed dendrometer records of daily increments using moving correlations and regression trees. Oak growth is affected by (i) dry and cold winters, resulting in root damage and water shortages during summer, (ii) a cool and wet March-April, hampering the onset of earlywood growth, and (iii) a hot and dry May-July period, reducing latewood formation. Latewood width increases when February P > 55 mm, March T > 3.3 °C, April P < 60 mm, May P > 50 mm, June T < 19 °C and August P > 40 mm. Latewood width decreases with tree age, mistletoe infestation and competition from neighbouring trees. These factors are responsible for different climate-growth responses. Infested oaks develop less latewood if T in June-July is high and this is associated with drought. In healthy oaks May P determines how quickly earlywood growth is completed and hence when latewood formation starts. Grouped trees that compete for soil water are more prone to June-July droughts but less harmed by cold springs than solitary oaks.
Databáze:	Katalog Knihovny AV ČR
Externí odkaz: