The Relationships Between Tracheid Characteristics And Tree-ring Of Chenshan Red-heart Chinese Fir And Their Responses To Climatic Factors

The anatomical characteristic of xylem is the representation of tree-ring in the dimension level of cell,and can explain the change of tree-ring in micro-level.Studying and researching the relationship between anatomical characteristic and the environment factor helps provide statistical result of dendroclimatology with the biological explanation.Samples were taken from red-heart Chinese fir,and tree trunk anatomy,anatomical microscopic observation of tree ring were adopted in this thesis to analyze the dendroclimatology,and the anatomical characteristics of tree-ring and their relationships with the environment factor.This article summarized the tree-ring growing features,xylem anatomical characteristics and others of Chenshan red-heart Chinese fir,and discussed the relationship between anatomical characteristic and climatic factor.The main results are as following:(1)The biggest average increment of red-heart Chinese fir appeared at the time of the 8th age,i.e.the quantitative mature age.The red heart wood appeared at the 9th age,and the rate of red section rose as the tree age getting older.The red section ratio of the 26 age forests can reach 59%,and the rate drops as the section sample taken higher.The whole ring width,and the early-and late-wood width increased then decreased from pith to bark,however,the late wood range small in width.Latewood percentage of each ring shall become decrease as time gone on,afterwards,the percentage shall increase and then decrease with the tree age,and extremely significantly decrease with the increase of tree-ring width.(2)There were significant positive correlations between the ring width of 9 and 15 age forests and temperature,however,there were significant negative correlations between the ring width of the 9,15 age forests and the precipitation and relative humidity.The ring width of the 26 age forest correlated significantly negatively with the highest temperature of July,August and September,and the lowest temperature of June.Yet,there were significant positive correlations between the 26 age ring width and the precipitation of January and October,the relative humidity in January and March.The latewood percentage with different climate factors greatly differed from one another.Generally,there was significant positive correlation between the ring width and temperature,but was significant negative correlation between the ring width and the precipitation and relative humidity.(3)The size of tracheid character of Chenshan red-heart Chinese fir increased with the tree-ring age from pith outwards.The radial variation pattern of tracheid length belonged to the Pashin ? model,and it indicated that the boundary of young wood and mature wood of red-heart Chinese fir was at the 14th years old.The tracheid length of 26 ages ranged from 992.03?m to 3531.86 ?m.The 15 ages'ranged from 1529.93?m?3209.00 ?m.The 9 ages'ranged 1314.00 ?m?2860.46 ?m.The tracheid length increased with the forest ages.However,the wall thickness decreased with the forest ages.The differences of tracheid characteristics among different age forests were both extremely significant(P<0.01).The characteristic between red-heart wood and white sapwood within 26 age forests showed an extreme significant difference.The differences of tracheid length and L/W between red-heart wood and white sapwood within 9 and 15 age forests were extremely significant.(4)The relationships between tracheid characteristics and ring width were very intimate.It was significant that ring width related negatively to tracheid length and L/W in the 26 and 15 age forests,and the positive correlation with the wall thickness in the 26 age forest was significant.In 9 age forest,the positive correlations between ring width and tracheid width,lumen diameter and LD/W were significant,and the WT/LD decreased significantly with the ring width.(5)The responses that the tracheid responded to climatic factors were different in various forests.The tracheid width of 9 and 15 age forests were both correlated positively with most monthly temperatures,and were correlated negatively with precipitation and relative humidity.In 26 age forests,the correlation between tracheid width and temperature was negative,but it was positive in the correlation between tracheid width precipitation and relative humidity.There were significant negative correlations in tracheid width of the 26 age forests with December average temperature of previous year,the lowest temperature of March and the highest temperature'of September,while,was significant positive correlation with September relative humidity.In 9 and 26 age forests,the tracheid length showed a positive correlation with temperature,but negative correlations with precipitation and relative humidity.The ones of the 15 age forest showed negative correlation with temperature.The tracheid length of 26 ages was significant positive correlation with April average temperature and the lowest temperature of July,but was significant negative correlation with the highest temperature of January,relative humidity of May and JuneThe wall thinckness of 9 and 15 age forests related positively to temperature,but correlated negatively with most monthly precipitation and relative humidity.In 15 age forest,the wall thinckness showed a significant positive correlation with the lowest temperature of July,and a significant negative correlation with precipitation of August.The wall thickness of 26 age forest was correlated negatively with temperature,but correlated positively with precipitation and relative humidity.There were significant negative correlations in the wall thickness of 26 age forest with the lowest temperature of February and October,average temperature of June and October.The wall thickness of 26 age forest correlated positively with November precipitation of previous year and September precipitation of current year,November relative humidity of previous year,June and October of current year;and was an extreme significant correlation with September relative humidity.This study explored the anatomical characteristics of the xylem and the responses that it responded to environmental factors,so as to make a more accurate positioning for the use of Chinese fir in different climatic areas and different segments of the trunk.It enriched the contents of forest ecology from the perspective of dendroclimatology,and provided basic datas and theoretical basis for the cultivation of red-heart Chinese fir and the utilization of high-value Chinese fir decorative materials.