Effects of Buried Wood on the Development of Populus tremuloides on Various Oil Sands Reclamation Soils.

Kaitlyn E Trepanier,Bradley D Pinno,Laura Manchola-Rojas

doi:10.3390/f13010042

Abstract

Buried wood is an important but understudied component of reclamation soils. We examined the impacts of buried wood amounts and species on the growth of the common reclamation tree species trembling aspen (Populus tremuloides). In a greenhouse study, aspen seedlings were planted into four soil types, upland derived fine forest floor-mineral mix (fFFMM), coarse forest floor-mineral mix (cFFMM), and lowland derived peat and peat-mineral mix (PMM), that were mixed with either aspen or pine wood shavings at four concentrations (0%, 10%, 20% and 50% of total volume). Height and diameter growth, chlorophyll concentration, and leaf and stem biomass were measured. Soil nutrients and chemical properties were obtained from a parallel study. Buried wood primarily represents an input of carbon to the soil, increasing the C:N ratio, reducing the soil available nitrogen and potentially reducing plant growth. Soil type had the largest impact on aspen growth with fFFMM = peat > PMM > cFFMM. Buried wood type, i.e., aspen or pine, did not have an impact on aspen development, but the amount of buried wood did. In particular, there was an interaction between wood amount and soil type with a large reduction in aspen growth with wood additions of 10% and above on the more productive soils, but no reduction on the less productive soils.

Highlights

Within Alberta, Canada, oil sands surface mining has disturbed an area of 953 km2 out of 4800 km2 of surface mineable area, and all of this area must be reclaimed once industrial operations are complete [1,2,3]
There was a clear distinction in height among soil types (p < 0.001, Figure 1) representing differences in inherent productivity
The same pattern held for diameter, with peat having the largest diameter, followed by fine forest floor-mineral mix (fFFMM) (0.43 cm), peat-mineral mix (PMM) (0.41 cm), and coarse forest floor-mineral mix (cFFMM) (0.35 cm)

Summary

Introduction

Within Alberta, Canada, oil sands surface mining has disturbed an area of 953 km out of 4800 km of surface mineable area, and all of this area must be reclaimed once industrial operations are complete [1,2,3]. The area is cleared of merchantable timber and the remaining woody debris (ground logs, limbs, standing snags, stumps and twigs) is burnt or mulched to be used in reclamation projects, such as by incorporating it into the salvaged reclamation soils or by placing it on top of the reclamation soils [4]. Once the merchantable timber is removed, the soil is salvaged and either directly placed onto reclamation sites or stockpiled for future use. The aim of reclamation in the oil sands is to create a self-sustaining ecosystem that has an equivalent land capability to the ecosystem that was present pre-disturbance [1,4,5,6]. A self-sustaining ecosystem includes various components such as soil, plants, and wildlife, along with ecosystem processes such as primary productivity and nutrient cycling [6,7,8]. Within the soil, buried wood has the potential to alter nutrient availability, water holding capacity and microbial communities, but its impact on tree growth in these reclamation soils is not known [9,10,11]

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