The response of the radial growth of two tree species to
climatic factors before and after a sudden rise of regional temperature in 1988
was analyzed based on the research of Picea
obovata and Larix sibirica on the
southern slope of the Altay Mountains in Kazakhstan. The results showed that
there was a good correlation between the two standardized chronologies of the
two tree species, and also a high consistency with the stage of low-frequency
change and a high reliability of chronological series change. The GLK values of
the two chronologies were high, which indicated that their radial growth was
consistent. The radial growth of P.
obovata and L. sibirica was
faster at their young forest age but slower from the middle forest age to the
mature forest age in the study area. The variation trend of tree-ring width
index of these two tree species was consistent before and after the sudden rise
of temperature. Before the sudden rise of temperature, the tree-ring width
index of these two tree species increased unsignificantly with a slow decrease
of precipitation and a slow increase of temperature. However, after the sudden
rise of temperature, the tree-ring width index of P. obovata and L. sibirica was
in a significant decline trend with the slow increase of annual precipitation
and annual average temperature. This showed that there was a negative impact of
climate change on the growth of trees, and the growth of these two tree species
might be slowed down after the sudden rise of temperature. Under global
warming, the radial growth of P. obovata and L. sibirica was mainly restricted
by temperature, and the influence of precipitation was relatively low. The response
of L. sibirica to temperature was slightly
stronger than that of P. obovata. Holistically,
there was a unsignificant difference in response of the radial growth of these
two tree species to climate change. The response of the growth of these two
tree species to climatic factors before and after the sudden rise of regional
temperature in 1988 was analyzed. The results showed that, during the period
from 1960 and 1988, there was a significant negative response of tree-ring
width of L. sibirica to the
precipitation in May that year, and to the temperature in August last year. There
was a significant positive correlation between the radial growth of P. obovata and the precipitation in July
of that year, but a significant negative correlation between it and the
temperature in August last year. During the period from 1989 to 2016, the
response of L. sibirica to the
precipitation in May was no longer significant. Instead, there was a
significant negative correlation between the growth of L. sibirica and the temperature in May of that year and in August
last year. There was a weaker positive correlation and a higher negative
correlation between the growth of this tree species and the temperature in
growth season, or a change from positive correlation to negative correlation.
The significant correlation between the radial growth of P. obovata and the precipitation disappeared. Instead, a negative
correlation with temperature strengened, especially in August and October last
year. The results showed that the positive response of the tree-ring width of P. obovata and L. sibirica to precipitation decreased but the negative response to
temperature increased after the sudden rise of temperature. The response of the
radial growth of P. obovata and L. sibirica to climatic factors might
different after the sudden rise of temperature.
