Other Studies


Publication Summary for the Date Creek Experiment
Coates, K.D. and P. LePage. 2009.

This report summarizes all papers and reports from the Date Creek Experiment. There are many papers sumarized not related to the SORTIE-ND modeling research, but of interest to understanding the ecology and management of northern temperate forests of British Columbia

Effects of partial harvesting on susceptibility to windthrow
Coates, K.D., Canham, C.D., Hall, E.C. 2009.

A paper on this study is in preparation. In this study we address how partial harvesting affects the rates and patterns of windthrow in managed, complex-structured, mixed-species forests, using two complementary approaches: (1) measurement of rates of windthrow following experimental partial harvesting treatments, and (2) comparative field studies from sites that had experienced a wide range of prior harvest regimes and storm severities. Our specific objectives were to evaluate how harvest intensity and proximity to a logging-created edge affects susceptibility to windthrow for a suite of tree species in the interior cedar-hemlock forests of northwestern British Columbia. The comparative field study builds on the work of Canham et al. (2001) and results could be used to build a new windthrow behaviour in SORTIE-ND.

Abundance of secondary structure in lodgepole pine stands affected by the mountain pine beetle in the Cariboo-Chilcotin
Coates, K. David, Tlell Glover, Beth Henderson. 2009.

This study expanded the secondary structure study of Coates et al. (2006), see below, to the Cariboo-Chilcotin region of central British Columbia. Plots were selected from age class four and higher pine stands in the Quesnel, Williams Lake and 100 Mile House Timber Supply Areas. A total of 1,649 plots were obtained of which 1,109 were determined to be pine-leading. Secondary structure was abundant in all biogeoclimatic zones of the Cariboo-Chilcotin region and was consistent with results from other regions of British Columbia where pine-leading stands have been examined. The variable levels of secondary structure found in the Cariboo-Chilcotin region provide considerable management flexibility. The suitability of managing the secondary structure will depend on the value being considered (e.g., timber supply, hydrological recovery period). Plot data from this study could be used to initate SORTIE-ND for projections of future growth of unsalvaged stands in this region. 

Abundance of secondary structure in lodgepole pine stands affected by the mountain pine beetle
Coates, K. David ,Craig DeLong, Philip J. Burton, and Donald L. Sachs. 2006.

This paper reports on the abundance and extent of secondary structure in lodgepole pine stand types in north central British Columbia. Datasets (1083 plots)used in this study were drawn from mature and older pine stands in the Nadina, Vanderhoof and Prince George Forest Districts. The magnitude and extent of the current mountain pine beetle outbreak requires thoughtful planning to recover value from the impacted timber while maintaining other values and reducing impacts to future timber supplies. This report represents the first step in determining if secondary structure in pine-leading stand types can help mitigate mid-term timber supply short falls, by identifying the abundance and extent of secondary structure in these stand types. We also project future development of three stand types with good secondary structure using VDYP7 and SORTIE-ND.

We found that pine-leading stands had considerable variability in secondary structure across north central BC. Approximately 20-30% of the stands had sufficient secondary structure today to reasonably expect higher yields in the mid-term from these stands if left unsalvaged compared to a salvage and plant strategy. Approximately 20-25% of pine-leading stands had poor secondary structure and these stands should be first priority salvage and planting. There appears to be considerable potential to reduce the impact to mid-term timber supply and enhance biodiversity values, hydrologic recovery, visual quality and wildlife habitat by strategically protecting certain pine-leading stand types from immediate harvest and/or protecting secondary structure during salvage operations.

Gap disturbances in northern old-growth forests of British Columbia, Canada
Bartemucci, P., Coates, K.D., Harper, K., Wright, E.F. 2002.

This study was part of efforts to better quantify the role and importance of small-scale disturbances in northern latitude forests. Gap disturbances have been largely ignored in northern latitude forests, especially those with frequent large stand-destroying fires. In this study, we sampled in four major forest types of northern British Columbias with varying fire return intervals, stand composition and climate. We determined the amount of gap disturbance in northern latitude forests, identified the gap-forming processes, determined the spatial patterning of gaps, and characterized understory light regimes.

Gap sizes in northern British Columbia forests were at the upper end of ranges reported for other high latitude forests and were mostly larger than those in tropical and temperate deciduous forests. Abundant gaps, large gap sizes, high numbers of gap makers per gap, and frequent gap expansion events suggest that gaps have long tenure in these forests. Snapped stems and standing dead mortality were the most common modes of mortality in all forest types resulting in little forest floor disturbance, creating few germination sites for seedling establishment. We found high mean light levels (16-27 % full sun), and little difference between non-gap and gap light environments. Our results suggest that gap dynamics in these forests differ fundamentally from those in temperate and tropical forest ecosystems. Old-growth forests and small-scale disturbances were prevalent in the high-latitude forests of British Columbia, which were traditionally considered fire-driven, large-scale disturbance systems.

Windthrow damage two years after partial cutting at the Date Creek silvicultural systems study in the Interior Cedar-Hemlock forests of northwestern British Columbia.
Coates, K.D. 1997.

Wind damage is a minor to moderate damage agent in the forests of northern British Columbia. The SORTIE-ND model has wind damage behaviours developed in the eastern US.

This study reports on wind damage in the interior cedar hemlock forests of the Date Creek Study. Partial cutting that removed either 30 or 60 percent of the volume as single trees or small groups up to 0.5 ha had little effect on wind damage to merchantable trees (greater than 17.5 cm diameter). On average, 6.7 stems per hectare of windthrow occurred across unlogged and logged units, representing approximately 1.9% of the standing trees. Over two years, 0.63 m2 ha-1 of merchantable basal area was damaged or 1.5% of the original standing basal area. In the partial cuts, 2.2% of the trees were damaged compared to 1.1% in unlogged areas. The 1.1% increase in damage in partial cut units was well below the 10% effect size considered large enough to warrant either management intervention or to deem the partial cutting a failure. The greatest wind damage occurred in the old-growth stands. For 8 of the 9 tree species examined, no individual tree characteristics seemed to predispose them to wind damage. amabilis fir, trembling aspen and subalpine fir were the most susceptible species to windthrow. 

A gap-based approach for development of silvicultural systems to address ecosystem management objectives
Coates, K.D. and Burton, P. J. 1997.

This paper explains thinking around research and management of complex-structured stands during the early days of the Date Creek Experiment. Protection and production of more diverse forest values demands consideration of the fine-scale variability found within forest stands and an understanding of the spatial and temporal response of forest ecosystems to manipulation. Studies of gap dynamics have contributed significantly to our understanding of the role of small-scale disturbance in forest ecosystems, but have been little used by foresters for predicting ecosystem response to partial cutting. This paper reviews the gap dynamics literature paying special attention to papers that use gap size or position as predictive variables for responses indicative of silvicultural success or maintenance of ecosystem function. Like canopy gaps created by natural tree death or windthrow, gaps are also generated by silvicultural systems which remove dominant trees. The paper describes a gap-based approach for study of stand response to silvicultural manipulation that: 1) aids development of cutting prescriptions that maintain functional mature or old-growth conditions; 2) refines and extends our understanding of how biological structures, organisms and ecosystem processes are affected by fine-scale variation within stands; and 3) leads to development of novel silvicultural systems that meet timber production objectives without compromising ecosystem management principles.