Ecological characteristics of production and decomposition in a hypermaritime peatland-forest complex near Prince Rupert, British Columbia

Vegetation, environmental factors, net primary production (NPP), and decomposition were studied in both a natural bog-forest complex and an experimental clear-cut forest in the hypermaritime north coast of British Columbia, in an attempt to establish some empirical scientific background on the dynamics of peatland-forest ecosystems and to clarify the relationships between clear-cutting and paludification.; The entire bog-forest vegetation gradient from the open bog to the bog woodland to the bog forest to the Thuja-Gaultheria forest to the Tsuga-Rhytidiadelphus forest was primarily explained by steepness of slope and lowest level of groundwater table fluctuation. Environmental conditions in the upland Tsuga-Rhytidiadelphus forest were considerably different from the wet Thuja-Gaultheria forest and peatland vegetation types, but the differences were relatively small among the Thuja-Gaultheria forest and peatland vegetation types.; Mosses are the major components of peatland vegetation at the study site. Their growth was positively correlated with precipitation, and the temperature thresholds for their growth appeared to be low. This suggests that the abundant precipitation in the region is advantageous for the moss growth, and the mild temperature throughout the year may make even winter growth possible. These factors explain the relatively greater moss growth rate and production in the hypermaritime region compared to other regions.; The aboveground NPP was significantly different among the micro-communities in the natural open bog. A micro-community that had high aboveground NPP had high moss NPP, mainly Sphagnum NPP. NPP in hummock Sphagnum-dominated open peatlands in hypermaritime region was expected to be great compared to the peatlands at the same latitude in Canada.; Decomposition potential was not significantly different among the five vegetation types in the bog-forest complex at landscape level, whereas the significant difference was found within the open bog among the micro-communities. The difference was explained by local hydrological conditions. Decomposition potential was greater in the hypermaritime sloping peatlands than in the continental peatlands in Canada.; Clear-cutting and mounding operations have probably initiated paludification at the experimental site of the Thuja/Tsuga forest. Although lowest level of groundwater table fluctuation was the only major environmental difference among the Thuja-Gaultheria forest and peatland vegetation types in the natural bog-forest complex, clear-cutting led to the rise in the groundwater table, which reduced the difference among them. The mounding operation further contributed to create the hollows where the water table was high and to expose bare peat surfaces where competition was reduced, which facilitated the Sphagnum invasion. The vertical growth rate of Sphagnum at the clear-cut site was about the same or even faster than at the natural site. The decomposition rate at the clear-cut site and at the natural site was not significantly different or even smaller at the clear-cut site. These facts suggest that peat accumulation potential of Sphagnum patches at the clear-cut site is comparable to that in natural peatlands. The mounding operation, alone, is not promising for forest regeneration in wet Thuja/Tsuga forests in the hypermaritime region.