The Altai Siberian stone pine forests: undisturbed and stable.
The Siberian stone pine (Pinus sibirica) old-age forests of the Central Altai is an almost unique example of a natural ecosystem with a minimal direct impact of human activities All known forests of this type are isolated in the relatively undisturbed valley of the Aktru river. The forests successfully survived the Little Ice Age and demonstrate significant stability under modern climate change. The dendrochronological studies suggest these forests existed and much probably remained virtually unchanged for 650+ years in the past.
Despite the similar age and resilience these old forests exist in 4 sustainable variations; each one is the forest adaptation to the peculiarities of their respective ecotopes (degree of slope, peculiarities of the ground and soil). Full α-biodiversity of these forests includes 112 vascular plant species and 46 mosses and lichens. We believe the most important aspects of these forest stability are the exceptional ecological amplitude of adult Pinus sibirica and the powerful environment-changing abilities of this species. The significant peculiarity of these forests is the presence of cyclic succession necessary for the regeneration of the forest. The age structure of the forests suggests it can be disrupted or even stopped because of the vulnerability of Pinus seedlings and young trees to climate changes: the dendroclinatic studies indicate the forest include 2 large regeneration gaps related to significant coolings. The important element of stability which compensates the vulnerability is longevity of Siberian stone pine (average tree life span is about 550-600 years) and ability to produce seeds to the death of the tree. The current level of climate change is not strong enough to disrupt the cycle; it is more likely it is favorable for modern Stone pine forests regeneration and slow expansion of the species up by the valley slopes.
The monitoring of regeneration suggests these forests are at least stable under modern climate changes.