Tillväxteffekter på lång sikt av gödsling i äldre tallbestånd : studie som undersöker huruvida gödsling påverkar tillväxten på lång sikt

Sammanfattning

The purpose of this study was to determine if fertilization had an impact on the long-term growth effects of pine forest on less fertile ground. It was done by using data from field trials to compare fertilized plots with control plots, and with that get results whether fertilization influences growth or not in a longer period, but also how production and height development acted together. The stands in the two fields trials were fertilized during the 1960 and 1970s, and the long-term effects was investigated in a period of 40 – 50 years after the fertilization was done. The growth aspects that were examined was total production, volume increment and upper height. The results showed an increase in growth both in a short time and over a long time. The results from the study were also tested statistically to determine if there were any difference between the first and last revision for fertilized and control plots, and to see if there were any difference between the field trials. What could be seen was that height development was central in this study, a greater height makes all other growth factors increase over time. If the height increases rapidly and stays higher over time, then fertilization has a long-term effect on growth. The main results of this study were that long-term effects on growth from fertilization could be observed. The plots treated with fertilization got higher site index than the plots with no treatment. Other studies that were investigated did not show an increase in height development from fertilization, and those studies could not prove any long-term effects either.