Timo Korkalainen , Pekka Pietiläinen, Alfred Colpaert

Pinus sylvestris L. stands in three fertilized and drained peatlands in northern Finland

Korkalainen T., Pietiläinen P., Colpaert A. Pinus sylvestris L. stands in three fertilized and drained peatlands in northern Finland.

English title: The effect of total peat nitrogen on the height and volume of Scots pine

Abstract

The total peat nitrogen (N) concentration is an important factor when determining stand heights and volumes in areas of poor climate conditions. This study explores the effect of peat nitrogen on the height and volume of Scots pine (Pinus sylvestris L.) stands in drained peatland sites in three temperature sum regions (Susivaara 909, Hepokangas 930, and Haapua 987 dd) in northern Finland. The peat nitrogen concentration ranged from 0.7% to 3.0%. In all experimental fields, the concentrations of foliar nutrients (nitrogen (N), potassium (K), phosphorus (P), and boron (B)) were analyzed. A total of 550 peat samples, 440 foliar samples, and 1687 sample trees were measured. We found nitrogen deficiencies in the foliar samples of all experimental fields. At Haapua, the stands were the highest, about 140 dm, when the peat N-concentration was at its maximum (3.0%). In the areas of Susivaara and Hepokangas, the stand heights were lower than in Haapua, about 90 dm, when N-concentrations of peat were at their maximum (2.5% and 2.8%). The stand volumes were largest at Haapua (about 190 m3/ha, N = 3.0%). At Susivaara (80 m3/ha, N = 2.5%) and Hepokangas (70 m3/ha, N = 2.8%), lower stand volumes were measured. We found a strong positive relationship between peat N-concentration and stand height as well as stand volume at Hepokangas and Haapua. At Susivaara, however, this relationship was weak. The results show that the total peat nitrogen concentration strongly affects stand height and volume on drained peatlands. The information of this study can be utilized, for example, when assessing the feasibility of forest management practices, such as the profitability of ditch network maintenance and fertilizations on peatlands.

Keywords
Drainage; Scots pine; stand volume; peat nitrogen; foliar nutrient; stand height

Received 31 October 2017 Published 1 January 2007

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