Effect Of Forest Regeneration On Loss Of Nutrient

In the subtropical evergreen broadleaf forest felling,we adopted the method of tree planting after burning and artificial measures promoting natural regeneration(called artificial promote the update)with unburning.There were respectively established Castanopsis carlesll young plantation,Cunninghamia lanceolata young plantation and promoting updating young forest,and set runoff plot in the experimental site.During April 2012 and March 2014,quantitative researching affects of rainfall,runoff and different ways of update on loss of nutrient,for forest managing and operating providing scientific evidence and theory in future.The main results showed that:(1)The monthly runoff of silvicultural young plantation and promote update young forest were showed significant seasonal changes with the same of rainfall,and maximum and minimum value with significant different were appearing spring and autumn,respectively(P<0.05).At update early,the size of the relationship between monthly runoff was the Castanopsis Lanceolata young plantation>Cunninghamia Lanceolata young plantation>promote update young forest.Annual runoff of promote update young forest and silvicultural young plantation were respectively 418,1617 and 1071 mm.(2)Runoff of promote update young forest and Cunninghamia Lanceolata young plantation with the mounts of rainfall and rainfall intensity showed a highly significant positive correlation(p<0.01).Runoff of Castanopsis Lanceolata young plantation also has a highly significant positive correlation with mounts of rainfall(p<0.01),but not significant correlation with rainfall intensity.The effect of mounts of rainfall was higher than rainfall intensity.Mounts of rainfall and rainfall inensity has a greatest influence on runoff of promote update young forest.(3)Initial different ways of update,monthly concentration and flux of nutrient had a obvious seasonal variations,however the maximum and minimum value of monthly concentration and flux were not arisen at the same season three from young plantations.Generally,concentrations of Na and K in the runoff of promote update young forest were greater than silvicultural young plantation,as well as concentrations of Ca and Mg were lower.Monthly fluxes of nutrient were the silvicultural young plantation higher than promote update young forest.(4)Annual fluxes of nutrient of silvicultural young plantation were higher than promote update young forest.Annual fluxes of other nutrient showed a significantly higher of Castanopsis Lanceolata young plantation than the promote update young forest(P<0.05),excepting K.Cunninghamia Lanceolata young plantation with the two was not significant different.Annual flux of nutrient was K>Ca>Na>Mg.(5)Mounts of rainfall,rainfall intensity and runoff were negative correlation with concentrations of nutrient,and were positive correlation with fluxes of mutrient.Factors of influence were the size of runoff>mounts of rainfall>rainfall intensity.