Studies On The Forest Damage And Restoration Response To Ice Storm, And Fast Recovery Methods In Nanling

The impacts of ice storm on forest and the ecological restoration are critical to forestrestoration and management. The severe ice storm events occurred in2008in southernChina. In order to study the response to the damage and restoration and to find restorationways to fast recover the damaged forests. We selected the typical types of forest inTianjing Mountain (located in Guangdong province,southern China). The dependence oftree age underlying vegetation damage and subsequent recovery were studied throughlong term oriented plots. We suggested fast recovery methods to different damagedforests by comparing vegetation changes and soil recovery in three subtropical foresttypes, coniferous forest(CF), mixed forest(MF), and broad-leaved forest(BF) in theTianjing Mountains, South China. The study is helpful to develop the control andmanagement of forest when ice storm events take place and to provide forest fastrecovery modes in practice. The main results are as follows: (1) The damage and recovery rates were dependent on tree ageThe results showed that damage and recovery rates were both dependent on tree age,with the proportion of damaged vegetation increasing with age(estimated by diameter atbreast height, DBH) in all three forest types and gradually plateauing. Significantvariation occurred among forest types. Young trees in the coniferous forest were morevulnerable than those in the broad-leaved forest. The type of damage also varied with treeage in different ways in the three forest types. The proportion of young seedlings thatwere uprooted(the most severe type of damage) was highest in the coniferous forest. Inthe mixed forest, young trees were significantly more likely to be uprooted than seedlingsand adult trees, while in the broad-leaved forest, the proportion of uprooted adult treeswas significantly higher than that of seedlings and young trees.There were differences in tree age dependence among recovery of forest type. In theconiferous forest, the recovery rate of trees with broken trunks or crowns(DBH>2.5cm)increased with tree age. However, in the mixed and broad-leaved forests, no obviouscorrelation between the recovery rate of trees with broken trunks or crowns and tree agewas observed.Trees with severe root damage did not recover, they were uprooted and died. Inthese forests, vegetation damage and recovery showed tree age dependencies, whichvaried with tree shape, forest type, and damage type. Understanding this dependency willguide restoration after ice storm disturbances.(2) Revealed the recovery process of forest soil after ice storm eventsThe decrease of soil pH is related to forest litter after ice storm events. Great amountof litter leads to soil pH decreased sharply at the early stage of ice storm events. Then soilpH gradually recovered to the level before the disaster for2-3years later (soil pHreturned to4.5-4.7).Gradually restored vegetation is beneficial to nutrient (e.g. organic matter, totalnitrogen and total phosphorus) accumulation. Tremendous abnormal litter lead tonutrients accumulated in early period of ice storm events. At the beginning, the N andorganic matter in soil show a sharp increase trend. Afterwards, the nutrients in soilshowed a reduction trend year after year since the canopy was damaged and the stormwater retention ability reduction. After the canopy recovery, there was a slow recovery trend in soil organic matter and N etc.(3) Suggested forest fast recovery methods through soil adjustmentSoil pH adjustment method. Compared with the control forest, liming improved therecovery of tree growth and soil nutrient content in all three types of forests. Over theexperimental period, liming had significantly facilitated the recovery of mixed andbroad-leaved forests, but exerted little effect on the recovery of coniferous forest.Soil Phosphate method. Compared with the control forest, phosphate acceleratedrestoration of MF and BF. The integrative results showed that P method enhanced the soileffective P of all the3forest types, and improved soil pH of CF, while P method had nosignificant effects on soil pH of the other2forests (MF and BF).Soil manure method. The tree growth rate increased by soil manure application atthe initial recovery stage, and the restoration of first application was better than thesecond application. The overall results of5-year recovery showed that compared with thecontrol forest, manure method promoted the recovery rate of the trees in MF and BF,while no significant promotion occurred in CF though the tree growth rate of CF is thefastest.Overall, soil pH adjustment method (lime application) was the economical andeffective way, especially for the recovery of mixed and broad-leaved forests. Papplication was the most effective method, soil manure method was the weakest inrecovery effectiveness.