**1. Introduction**

118 Sustainable Forest Management – Case Studies

Cruz, P., Honeyman, P., & Caballero, C. (2005). Propuesta metodológica de ordenación

Davis, L. S., & Johnson, K. N. (1987). *Forest management*. McGraw-Hill, ISBN 634-928-000-

FAO. (1993). Forest resources assessment 1990: Tropical countries. FAO *Forestry Paper*, No.

FAO. (2005). *State of the world's forests 2005*, Food and Agriculture Organization of the United

Gonzáles, J. M., Piqué, M., & Vericat, P. (2006). *Manual de ordenación por rodales*. Gestión multifuncional de los espacios forestales. Norprint, ISBN 84-690-3133-3, Barcelona Hernando, A., Tejera, R., Velázques, J., & Ñuñez, M.V. (2010). Quantitatively defining the

Irvine, R.J., Fiorini, S., Yearley, S., McLeod, J. E., Turner, A., Armstrong, H., White, P. C. L., &

ITTO. (1990). ITTO guidelines for the sustainable management of natural tropical forests. *Technical Series 5*. International Tropical Timber Organization, Yokohama, Japan. Lund, H. Gyde. (2009). *What is a degraded forest?* White paper prepared for FAO. Retrieved

Mc Evoy, T. J. (2004). *Positive impact forestry: a sustainable approach to managing woodlands*.

MMA. (2008). Instrução Normativa nº 6, de 23 de setembro de 2008. Reconhece espécies da

Oliveira, Y. M. M. de. (2000). Investigation of remote sensing for assessing and monitoring

Putz, F. E., & Pinard, M. A. (1993). Reduced-impact logging as a carbon-offset method. *Cons.* 

Rivera, H. (2007). Ordenamento territorial de áreas florestais utilizando avaliação multicritério

Rosot, M. A. D. (2007). Manejo florestal de uso múltiplo: uma alternativa contra a extinção

Rosot, M. A. D., Oliveira, Y. M. M. de, Rivera, H., Cruz, P. & Mattos, P.P. (2006). Desarrollo

Smith, W. B., Miles, P. D., Perry, C. H. & Pugh, S. A. (2009). *Forest resources of the United* 

flora brasileira ameaçadas de extinção e revoga a Portaria Normativa Ibama no 37- N, de 3 de abril de 1992. Diário Oficial [da República Federativa do Brasil], Brasília

the Araucaria Forest region of Brazil. Thesis (Doctor of Philosophy). Department of

apoiada por geoprocessamento, fitossociologia e análise multivariada. Curitiba. Thesis (MSc). Department of Forest Engeneering. Universidade Federal do Paraná, Curitiba Rivera, H., Rudloff, A. & Cruz, P. (2002). *Plan de Ordenación de la Reserva Nacional Valdivia*.

da floresta com Araucária? *Pesquisa Florestal Brasileira*, Colombo, n. 55, pp. 75-85,

de un modelo de plan de manejo para áreas protegidas en bosques con araucaria en el sur de Brasil, *Proceedings of IUFRO Second LatinAmerican Congress*. La Serena,

*States, 2007*. WO GTR-78. USDA Forest Service, Washington Office, Washington, D.C., USA. Retrieved from http://www.fs.fed.us/nrs/pubs/gtr/gtr\_wo78.pdf

from http://home.comcast.net/~gyde/2009forest\_degrade.doc

Island Press. pp 268, ISBN 1-55963-788-9 Washington, D.C.

de 24/09/2008, nº 185, seção 1, pp. 75

*Biol*. 7, pp. 755-757, ISSN 0888-8892

CONAF. Santiago

ISSN 1809-3647

Chile, October, 2006

Plant Sciences, University of Oxford. Oxford.

conservation status of Natura 2000 forest habitats and improving management options for enhancing biodiversity. *Biodiversity and Conservation*, Vol.19, No. 8, pp.

Van Der Wal, R. (2009). Can managers inform models? Integrating local knowledge into models of red deer habitat use. *J. of Appl. Ecol*., 46, 2, pp. 344–352, ISSN 0021-8901

(August 2005), pp. 57-70, ISSN 0717-9200

Nations, ISBN 97-892-510518-70, Rome, Italy

000-000-0, New York

112, ISBN 92-5-103390-0

2221-2233, ISSN 0960-3115

forestal, aplicación a bosques de lenga en la XI Región. *Bosque,* Vol.26, No.2,

In many forests, timber harvesting is displacing natural disturbance (e.g., wildfire, wind, insects and disease) as the major agent of ecosystem disturbance. There is a growing concern over the impacts of intensive timber harvesting on the long-term site productivity (Nambiar et al., 1990; Nambiar and Sands, 1993; Johnson, 1994). The significant yield decline of Chinese fir (*Cunninghamia lanceolata* [Lamb] Hook) in southern China (Yu, 1988; Sheng and Xue, 1992) and of radiata pine (*Pinus radiata* D. Don) in southeastern Australia (Keeves, 1966; Squire, 1983) and New Zealand (Whyte, 1973) after several forest-harvest rotations exemplifies this concern, and the issue has gained renewed attention as interest has grown in forest certification, biodiversity, protection, forest carbon management and sustainability. A key issue in the discussion of sustainability is the comparability in ecological impacts between timber harvesting and natural disturbance (e.g., wildfire, insects, and disease). Much of the focus in this discussion has been on the characteristics that clear-cutting and natural disturbance have in common (Hammond, 1991; Keenan and Kimmins, 1993). However, the debate has frequently been frustrated by the lack of an adequate description of the range of ecological effects of both natural disturbance and forest harvesting. A variety of recent initiatives in forest policy in both the United States and Canada have emphasized natural disturbance processes and their structural consequences as models of forest management (Lertzman et al., 1997). However, implementing this approach is often limited by our incomplete understanding of natural disturbance regimes (Lertzman and Fall, 1998; Perera and Buse, 2004). Many studies have demonstrated importance of wildfire disturbance in forest ecosystems (Attiwill, 1994; Lertzman and Fall, 1998). If natural disturbance is fundamental to the development of forest ecosystems, then our management of natural areas should be based on an understanding of disturbance processes (Attiwill, 1994; Poff et al., 1997; Richter et al., 1997; Andison, 2000; Johnson et al., 2003)). This also highlights that ecological impacts of harvesting must be evaluated within a broad disturbance context. In the British Columbia (BC) interior forest ecosystems that are described as having a

natural disturbance type maintained by frequent stand-initiating fires, forest managers are

Sustainable Forest Management in a Disturbance

pine but can cause severe losses of volume production.

**3. Methods** 

**3.1 Field investigation** 

between SOH and WTH sites.

Context: A Case Study of Canadian Sub-Boreal Forests 121

Wildfire is a common, natural disturbance which cycles this type of forest about every 100 - 125 years (mean fire return interval in the SBPS Zone, J. Parminter, Ministry of Forests, Victoria, British Columbia). Other natural disturbance agents such as mountain pine beetles (*Dendroctonus ponderosae* Hopk) and dwarf mistletoe (*Arceuthobium americanum* Nutt) are common in the study area. The former can cause extensive tree mortality, and much of the harvesting in the study area was in stands where some (about 5-25%) of the dominant trees had been killed by mountain pine beetles. Dwarf mistletoe does not usually kill lodgepole

There are two types of timber harvesting including stem-only harvesting (SOH) and wholetree harvesting (WTH) applied in lodgepole pine forests in the central interior of British Columbia. WTH removes most of the above-ground woody biomass including crown materials while SOH removes most of the above-ground woody biomass but leaves crown materials on the site. Concern has focused on the ecological impacts of the removal of nutrient-rich crown materials, and in WTH such removal may result in considerably more

A combination of field investigation with ecosystem modeling was used for this study. The purpose of the field survey is to quantify the differences immediately following wildfire disturbance and harvesting, while the ecosystem modeling is to evaluate the long-term implication of those differences in site productivity. The ecosystem model FORECAST, or its forerunner FORCYTE, has been used as a management evaluation tool in several types of forest ecosystems (Sachs and Sollins, 1986; Kellomäki and Seppälä, 1987; Wang et al., 1995; Wei and Kimmins, 1995; Morris et al., 1997; Wei et al., 2000; Seely et al., 2002; Welham et al., 2002). The model was specifically designed to examine the impacts of different management strategies or natural disturbance regimes on long-term site productivity. A brief description of the FORECAST model approach is presented in the next section; details are found in

WD in this study includes CWD and fine woody debris (FWD). We define CWD as woody stems 2.5 cm diameter and FWD as woody stems < 2.5 cm diameter. We investigated FWD as well as CWD as the former should account for the major difference in WD loading

Thirteen plots (five for WTH and four each for wildfire disturbance and SOH) with records of the time of disturbance were located, interspersed across the study area. Most selected plots were harvested or burned within less than 20 years ago, with an exception of the plot burned in 1961. It was not possible to locate more fire-killed plots because no records are available for the fires occurred 30 years ago, and because recent fire protection in the area

The line intersect sampling method was employed to quantify WD volume (McRae et al., 1979). This involves 3 lines (each 30 m in length) laid out in an equilateral triangle. The triangular layout is used to minimize bias in situations where the logs are not randomly

site nutrient depletion. For this study, we included both harvesting methods.

Kimmins (1993); Seely et al., (1999); and Kimmins et al., (1999).

**3.1.1 Measurements of mass of above-ground WD** 

has limited the number of fire disturbances.

particularly interested in understanding natural wildfire disturbances in order to maintain the ecological patterns and functions of these forests (Parminter, 1998; Kimmins, 2000; Wei et al. 2003). In these areas, wildfire disturbance is part of natural ecosystem processes, and its functions are, from a long-term perspective, part of natural variability. Lodgepole pine forest (*Pinus contorta ssp. latifolia* Engelm. ex S. Wats.) is a major type of forests in the central interior of BC, and concerns have been expressed over potential impacts of intensive timber harvesting on long-term site productivity (Kimmins, 1993; Wei et al., 1997).

Both timber harvesting and wildfire disturbances can vary substantially in size, intensity, severity, frequency and internal heterogeneity, greatly complicating comparisons of the effects of different disturbance types. The differences relate to differences in forest type, topography, timing of the disturbance, local management methods, and management objectives (Lertzman and Fall, 1998; Parminter, 1998). From a nutrient perspective, a major difference between timber harvesting and wildfire disturbance is the biomass of woody debris (WD) left in the ecosystem, and the quantity of nutrients removed.

WD, particularly coarse woody debris (CWD), has been shown to be an important structural and functional element in many forested ecosystems (Lambert et al., 1980; Sollins, 1982; Harmon et al., 1986; Spies et al., 1988). It provides a key habitat component (especially large logs) for many forms of wildlife (Reynolds et al. 1992). Studies by Harvey et al. (1981) and Harvey et al. (1987) showed that organic materials, especially humus and buried residue in the advanced stage of decay, are excellent sites for the formation of ectomycorrhizal root tips. Graham et al. (1994) used ecotomycorrhizal activity as a primary indicator of a healthy forest soil. Further, CWD may play a significant role in long-term nutrient cycling; it can be an important site for asymbiotic nitrogen fixation, and it acts as a source of slow nutrient release during its long period of decay.

This paper summarizes a series of our research and publications in lodgepole pine forests in the sub-boreal regions of British Columbia, Canada. The objectives of this study are: (1) to quantify the difference in the mass and nutrients of woody debris remaining immediately following harvesting and wildfire disturbances; (2) to evaluate long-term implications of those differences in site productivity; and (3) to determine the management strategies for achieving sustainability of long-term site productivity in lodgepole pine forests in the BC interior.
