The Study Of Topographic Controls On Altitudinal Belt On Changbai Mountain

Topography is the leading factor that affects mountain vegetation distribution.The control mechanisms of topography on altitudinal belt are critical tounderstanding altitudinal belt dynamics and future changes. These mechanisms havenot been understood quite well enough because of increasing human disturbance,without proper method and low data resolution. In this study, the relationshipbetween the altitudinal belt and topography was analyzed based on high spatialresolution remote sensing data and a digital elevation model in north slope inChangbai Mountain with little human disturbance. Future altitudinal belt patternswere also predicted. The results showed that:(1) On the north slope of Changbai Mountain, altitudinal belt change gradually.The altitudinal belt pattern has heterogeneous changes in the horizontal direction.Every altitudinal belt has its unique characteristics. The birch forest zone is thenarrowest. The evergreen coniferous forest zone is the widest. The boundary betweenbirch forest zone and evergreen coniferous forest zone is a sharp transition. Otherboundaries are gradual transition. The boundary is curved, increased from northwestto northeast in macro-aspect direction. Each belt’s elevation, width and shape haveheterogeneous changes in the horizontal direction. The change of treeline ecotone isthe most obvious.(2) Topography controls the heterogeneous changes in altitudinal belt pattern inthe horizontal direction. Different types of topography have different vegetationcomposition. In each elevation range, the vegetation pattern is determined bytopography composition and vegetation proportion of various topography type.(3) Topography controls the altitudinal belt pattern by affecting environmentalfactors. In each elevation range, the vegetation pattern is a function that depends onenvironment factors controlled by topography. Slope affects the altitudinal beltpattern by redistribution of solar radiation and soil moisture. Aspect affects thealtitudinal belt pattern by redistribution of soil moisture and snow cover. In alpinezone, the extreme environment cause by slope-aspect combination limit treedistribution. At the Changbai Mountain alpine belt, snow cover is the most commonextreme environment.(4) Topography controls the respose of altitudinal belt to climate warming. Thefuture altitudinal belt pattern is controlled by new temberature mechanisms, newenvironmental factors and the reallocation effect of topography. Different types of topography have different reactions to global warming. In the short term, thecoverage rate of trees will not increase in all topography types. Global warming willovercome the extreme low temperature limit. The changes in other environmentalfactors caused by increasing temperatures might result in negative or even extremelybad effects on trees.(5) In association with a rise in temperature of0.5℃, the vegetation compositionof Changbai Mountain will change dramatically. Except for alpine tundra, otheraltitudinal belts will demonstrate an upward trend. The dark coniferous forest areawill increase, the area of other altitudinal belt will reduce. The transition zonebetween Korean pine forest and dark coniferous forest will become narrower andsmaller, as will treeline ecotone. The timberline will advance. The limit of tree maynot be significantly changed.