Operational Trials of Cut-To-Length Harvesting of Poplar in a Mixed Wood Stand

Cut-to-length harvesting systems offer an alternative to conventional mechanical systems for thinning mixedwood stands. We evaluated the performance of a single-grip harvester and forwarder in a poplar-dominated mixedwood stand in Southern Ontario to quantify the effect of tree size and tree form on harvester productivity and harvesting cost, and to assess the damage caused by the harvesting operation to advance regeneration and residual trees. A single-tree selection silvicultural system was used. Individual trees were assigned a form index based on their visual estimates of limb size and stem form. The cut-to-length harvester produced 23.1 m3 per productive machine hour (PMH). Forwarder productivity was 17.2 m3/PMH. The results indicate a significant and positive relationship between harvester productivity and tree size (dbh) and tree form. Tree size (dbh) has the greatest influence on the unit cost of harvesting. At an average 27 cm dbh and extraction distance of 200 m, the stump-to-landing cost was approximately 10 US$/m3. As tree size increased, the unit cost of wood produced decreased. Damage to residual trees and advance regeneration was minimal. The results suggest that single-grip cut-to-length harvesting systems can be effective in managing poplar-dominated mixedwood stands

Stumpage Prices In Southwestern Ontario: A Hedonic Function Approach

Timber used in the production of lumber in Southwestern Ontario varies in a number of characteristics and the lump-sum stumpage price is expected to reflect differences in those characteristics. When heterogeneous inputs are used in production, the hedonic price function approach may be used to estimate marginal implicit values of the various input characteristics. Hedonic price functions have been estimated for timber in the region using pooled time-series cross-section data from a large sample of timber sales. The results indicate that volume, species composition, tree size, timber quality and distance to the purchasing mill will affect lump-sum stumpage prices. Estimates of the contributions that each of these characteristics makes to stumpage prices are presented

INTERNATIONAL TRADE IN FOREST PRODUCTS: AN OVERVIEW

This report provides an overview of the current status of world trade in forest products. Global production and major trade flows are presented. Domestic policies affecting trade, tariff and non-tariff barriers to trade, free trade agreements, and environmental issues and their potential implications for trade flows are also reviewed. Recent empirical approaches to modelling the spatial commodity and interregional trade in forest products are discussed. Finally, the report highlights significant gaps in our knowledge and understanding of the factors affecting trade flows and recommends areas for further research

Determination of tip transfer function for quantitative MFM using frequency domain filtering and least squares method

Abstract Magnetic force microscopy has unsurpassed capabilities in analysis of nanoscale and microscale magnetic samples and devices. Similar to other Scanning Probe Microscopy techniques, quantitative analysis remains a challenge. Despite large theoretical and practical progress in this area, present methods are seldom used due to their complexity and lack of systematic understanding of related uncertainties and recommended best practice. Use of the Tip Transfer Function (TTF) is a key concept in making Magnetic Force Microscopy measurements quantitative. We present a numerical study of several aspects of TTF reconstruction using multilayer samples with perpendicular magnetisation. We address the choice of numerical approach, impact of non-periodicity and windowing, suitable conventions for data normalisation and units, criteria for choice of regularisation parameter and experimental effects observed in real measurements. We present a simple regularisation parameter selection method based on TTF width and verify this approach via numerical experiments. Examples of TTF estimation are shown on both 2D and 3D experimental datasets. We give recommendations on best practices for robust TTF estimation, including the choice of windowing function, measurement strategy and dealing with experimental error sources. A method for synthetic MFM data generation, suitable for large scale numerical experiments is also presented

Local Thermophysical Properties Measurements on Polymers using Doped Silicon SThM Probe: Uncertainty Analysis and Interlaboratory Comparison

International audienc

SThM-based local thermomechanical analysis: Measurement intercomparison and uncertainty analysis

International audienc