Understanding how tree species respond to drought in their natural environment is needed to predict forest adaptation and management practices under global environmental changes.This study was carried out to determine...Understanding how tree species respond to drought in their natural environment is needed to predict forest adaptation and management practices under global environmental changes.This study was carried out to determine and compare physiological and biochemical responses to variations in environmental conditions during summer drought of mixed natural stands of Pinus nigra Arn.subsp.pallasiana(Lamb.)Holmboe and Pinus brutia Ten.Midday xylem water potential(ψmd),water relations,photosynthetic pigments,total soluble sugar and proline contents were investigated during the growing season.ψmd followed a similar seasonal trend in both species but P.nigra subsp.pallasiana had higher ψmd than P.brutia.The ψmd gradually decreased from June,reached its lowest value in August,and then increased again.Gradual decreases in the osmotic potential at turgor loss point(ψnTLP)were observed during the summer.Generally,ψnTLP was lower in P.brutia.Total soluble sugars decreased from April to June for P.brutia,then increased and stayed relatively constant August to October.Similar changes were found at lower values in P.nigra subsp.pallasiana.Prolin accumulation and photosynthetic pigments were higher in P.brutia.The results indicate that physiological and biochemical responses of both species against changing environmental conditions were in different degrees but followed similar trends.P.nigra subsp.pallasiana is more sensitive to summer drought than P.brutia in their natural environment.展开更多
We investigated the effects of precommercial thinning(PCT)applied at different levels on the growth parameters of natural Anatolian black pine stand.The experimental site was located in the province of Isparta in sout...We investigated the effects of precommercial thinning(PCT)applied at different levels on the growth parameters of natural Anatolian black pine stand.The experimental site was located in the province of Isparta in southern Turkey.PCT was set up using a randomized complete block design with three replicates and three treatments(control,2–2.5 m×–2.5 m and 3–3.5 m×–3.5 m spacing).The experimental plots were established in March 2014.At the end of the growing seasons for three years(2014–2016),growth parameters such as diameter,height and crown radius were measured.PCT was found to be significantly effective on diameter,height,individual tree basal area,and crown radius increment at the end of the third year(p<0.05).While diameter,individual tree basal area and crown radius increment increased with increasing PCT intensity,height increment was higher in control than PCT.Although the PCT treatments applied with 3–3.5 m spacing affected individual tree development positively,we need long-term results on wood quality and yield.According to the short-term results,it is thought that it is better to lower the stand closeness gradually,so,it may be advisable to apply PCT by 2–2.5 m×–2.5 m spacing.展开更多
基金The work was supported by the Suleyman Demirel University,Scientific Research Projects Coordination Unit(Project Number:4513-YL1-15).
文摘Understanding how tree species respond to drought in their natural environment is needed to predict forest adaptation and management practices under global environmental changes.This study was carried out to determine and compare physiological and biochemical responses to variations in environmental conditions during summer drought of mixed natural stands of Pinus nigra Arn.subsp.pallasiana(Lamb.)Holmboe and Pinus brutia Ten.Midday xylem water potential(ψmd),water relations,photosynthetic pigments,total soluble sugar and proline contents were investigated during the growing season.ψmd followed a similar seasonal trend in both species but P.nigra subsp.pallasiana had higher ψmd than P.brutia.The ψmd gradually decreased from June,reached its lowest value in August,and then increased again.Gradual decreases in the osmotic potential at turgor loss point(ψnTLP)were observed during the summer.Generally,ψnTLP was lower in P.brutia.Total soluble sugars decreased from April to June for P.brutia,then increased and stayed relatively constant August to October.Similar changes were found at lower values in P.nigra subsp.pallasiana.Prolin accumulation and photosynthetic pigments were higher in P.brutia.The results indicate that physiological and biochemical responses of both species against changing environmental conditions were in different degrees but followed similar trends.P.nigra subsp.pallasiana is more sensitive to summer drought than P.brutia in their natural environment.
基金This study was a part of the doctoral dissertation and supported by Suleyman Demirel University Projects(Project numbers:OYP-05241-DR14 and 4167-OYP-D2-14).
文摘We investigated the effects of precommercial thinning(PCT)applied at different levels on the growth parameters of natural Anatolian black pine stand.The experimental site was located in the province of Isparta in southern Turkey.PCT was set up using a randomized complete block design with three replicates and three treatments(control,2–2.5 m×–2.5 m and 3–3.5 m×–3.5 m spacing).The experimental plots were established in March 2014.At the end of the growing seasons for three years(2014–2016),growth parameters such as diameter,height and crown radius were measured.PCT was found to be significantly effective on diameter,height,individual tree basal area,and crown radius increment at the end of the third year(p<0.05).While diameter,individual tree basal area and crown radius increment increased with increasing PCT intensity,height increment was higher in control than PCT.Although the PCT treatments applied with 3–3.5 m spacing affected individual tree development positively,we need long-term results on wood quality and yield.According to the short-term results,it is thought that it is better to lower the stand closeness gradually,so,it may be advisable to apply PCT by 2–2.5 m×–2.5 m spacing.
