1- Department of Forestry, Faculty of Natural Resources, Mazandaran University, P.O.Box 737, Sari, Islamic
Republic of Iran.
2- Tarbiat Modarres University, Noor, Mazandaran, 46414, Islamic Republic of Iran.
Abstract: (6052 Views)
The impact of climatic variations on basal area growth of basswood (BA) (Tilia americana
L.), American beech (BE) (Fagus grandifolia Enrh.), bitternut hickory (BH) (Caria
cordiformis (Wang.) K. Koch), largetooth aspen (LA) (Populus grandidentata Michx.), red
maple (RM) (Acer rubrum L.), red oak (RO) (Quercus rubra L.), sugar maple (SM) (Acer
saccharum Marsh.), and white ash (WA) (Fraxinus americana L.) was studied in a southern
province of Quebec, Canada (45o 25 ’ N, 73 o 57 ’ W). In total, forty-eight climatic
variations of precipitation (P) (13 variables), temperature (T) (13 variables), heat index
(H), (11 variables), and evapotranspiration (11 variables) from the current (C) and past
three years (P1, P2, & P3) were tested in regression models to find the best model of the
relationship between those independent variables and the last ten years (1985-1994) of
basal area growth of the species. Simple individual linear and second degree, mixed, and
combination of multiple regression models were used to develop the best regression model
for each tree species, separately. The best models explained 79% , 80% , 99% , 91% ,
71%, 99% , 49% , and 98% of the total variance of the growth in BA, BE, BH, LA, RM,
RO, SM and WA, respectively. The growth in BH, LA, RM, RO, SM, and WA were more
associated with the previous year’s climatic variations rather than the current year’s.
Bitternut hickory, LA, RM, SM, and WA growth were more related to the first year
rather than the second or third preceding year variables. The June heat index of the third
previous year of variables explained only 7% of the growth of white ash. It was concluded
that the impact of climatic variables on tree growth may vary and may depend on the
species and other unknown variables. Also, the results suggested that the first and second
previous climatic variables have an important role on the growth of some species. American
beech, BH, RO, and WA seem to be a good species to use for the study in dendrochronological
and dendroclimatological studies.
Subject:
Forestry Received: 2010/05/16 | Accepted: 2010/05/16 | Published: 2010/05/16