Lab+4+Ponderosa+Pine+Forest+Restoration+%28Sinclair+Wash%29

LAB 4: PONDEROSA PINE FOREST RESTORATION Lab Goals:  Introduce you to the principles of restoration ecology as they are applied to Ponderosa Pine forests in northern Arizona.  Give you a chance to observe first-hand the difference between restored and unrestored Ponderosa Pine forest.  Provide you with the opportunity to collect and analyze environmental monitoring data. Key Terms and Concepts Controlled Burn/Prescribed Fire – These fires are set by professional foresters to reduce the fuel load on the forest floor. Most prescribed burns aim to mimic ground fires and to prevent crown fires. Crown Fire – Fire that goes into the canopy of the forest, killing large trees as well as grasses and shrubs. Diversity (ecological) – Variation in the physical characteristics of ecosystems across a landscape caused by variation in soil, slope, aspect, elevation, climate, and geology. Doghair Thicket – An area of many small trees growing very close together; often with intertwining trunks. Fuel Load – The amount of available and potentially combustible material. When fire is suppressed the level of pine needle litter (duff) accumulates to high levels, leading to a high fuel load. Restored Forest – An area of forest that has received a restoration treatment. An example of a restoration treatment is the removal of small-diameter trees to reduce (thin) tree density. Surface Fire – This type of fire burns the understory (grasses, shrubs, and small trees that grow near the ground) of the forest, which regenerates quickly after a fire . Unrestored Forest – An area of forest that has not received a restoration treatment. Introduction to Ecological Restoration: Ecosystems are dynamic systems. Even when ecosystems are at “equilibrium” they are not static – animals graze on vegetation, which opens up space for new plants to sprout, and old trees die and fall over during windstorms. Disturbance is a natural part of healthy ecosystems. Native plants and animals have evolved in the presence of natural disturbance regimes and some species even rely on these natural disturbances to open new habitat in which they can live.

Biodiversity (# of species) Time Natural Variation Degradation 1. Continued Decline 5. Desired State 4. Alternate States 2. Stays the Same 3. Recovers but later Declines Restoration Degraded Ecosystem in Need of Attention Figure 1. Ecosystems experience natural disturbances (shown as arrows) that reduce the biomass or number of species. Because these disturbances exist within a natural range of variation, biodiversity has adapted to recover from these disturbances. When humans impose novel disturbances on ecosystems, the system may be perturbed to the point where it cannot recover on its own. In these instances, humans can alter the ecosystem with the intent to “restore” biodiversity. Figure modified from Hobbs & Norton, 1996. Humans have become the primary source of disturbance in many ecosystems. Humans can create novel disturbances, alter natural disturbance regimes, or suppress natural disturbances altogether. All of these changes alter natural ecosystems and can reduce or alter biodiversity. For example, dams create new disturbances by impeding the movement of fish along the stream. They alter natural flood patterns by reducing spring snowmelt floods and releasing more water in summer than in a natural river. They also suppress natural disturbances by capturing summer monsoon storms (which would cause tremendous floods) in the reservoir behind the dam. Ecological restoration is the process of returning a degraded ecosystem to a more natural trajectory. Across the world, environmental scientists are working to restore wetlands, savannahs, coastal areas, plains, and forests, in order to allow these ecosystems to perform their natural environmental functions, such as providing habitat for wildlife, purifying water, preventing erosion or catastrophic fire, or even to better provide natural resources for human use. Ponderosa Pine Forest Restoration Background Fire has long played a role in the evolution of forest and woodland communities throughout the western United States (Parsons et al. 1986, Kilgore 1981). In fact, many species and forest types worldwide are dependent upon a particular frequency and intensity of fire for survival (Mooney, 1981, Parsons et al. 1986). Ponderosa Pine ecosystems are widely recognized as a classic example of a fire-dependent community. 2

Southwestern Ponderosa Pine Forest Restoration Ecological Restoration Institute, Northern Arizona University People working to restore ecosystems around the world have, broadly speaking, used combinations of two different approaches: the structural approach and the process approach (SER 2002). A structural approach seeks to quickly return the structure of a given ecosystem to what it was before it was disturbed. A process approach seeks to return core ecological processes to the role they had before disturbance took place. In southwestern ponderosa pine forest ecosystems, a structural approach seeks to quickly return forest structure - that is, the placement and growth patterns of both trees and understory plants - to what it was before the disturbances of Euro-American settlement. A process approach, on the other hand, seeks to allow the keystone processes that shaped the forests, especially fire, to shape the forests again without making an explicit decision about precisely what the forest’s structure should look like. There is a great deal of overlap between these two approaches, and in fact every workable restoration solution for heavily altered forests needs to incorporate both. The “pre- settlement model” approach developed at Northern Arizona University seeks to quickly return tree densities to what they were in pre-Euro-American settlement times through thinning, but it does so in order to allow low-intensity fire to safely shape forest structure in the future without the threat of unnaturally intense crown fires (Covington et al . 1997). In other words, this approach alters structure so that the natural process can be returned. Approaches that emphasize the use of fire while calling for less structural manipulation - such as the Natural Processes Restoration Model prescription - also do require some thinning before fire can be reintroduced, since even a carefully planned prescribed fire in an unthinned forest can have disastrous consequences. Any meaningful restoration treatment has to address both forest structure and ecological processes. In ponderosa pine forests, any successful treatment has to permit the reintroduction of the frequent low-intensity fires that will shape these forests in the future. Source: Ecological Restoration Institute. Accessed 11-1-09. http://www.eri.nau.edu/en/restoration-resources/ecological-restoration-mainmenu- 133/restoration-approaches-mainmenu-199 4

Exercise 1: Collecting Forest Measurements In this activity you will collect data on tree size and tree density in a forest plot. QUESTION 1 (2 points): Before collecting quantitative data, start by making some qualitative observations about the forest plot. Include information about all aspects of the forest. QUESTION 2 (2 points): Based on what you know about forest restoration in ponderosa pine forests, and considering your qualitative observations from question 1, do you think this section of forest has received a restoration treatment (prescribed fire or mechanical thinning)? What specific observations did you consider when answering this question? Measure tree density and tree diameter in a forest plot:  Use a tape measure and flags (or pre-marked string) to measure an experimental plot , which in this lab is a square of land that is 25 meters by 25 meters.  Count the number of trees present in the plot and record the number.  Randomly choose 10 trees in the area and measure their diameter at breast height (the distance around the trunk 1.4m up from the ground surface).  Record the tree diameter (in centimeters) for each measured tree.  Calculate the average diameter of the trees in each treatment for each plot. This is done by adding up the diameters of all of the trees you measued and dividing by the total number of trees (10). (2 points) Tree diameters (cm) Total # of trees in the plot 1 2 3 4 5 6 7 8 9 10 Average 5

QUESTION 5 (2 points): In general, what are some factors that contribute to the type and diversity of ground cover in a forest plot such as this? QUESTION 6 (2 points): In previous semesters, ENV 101 students have visited both treated and untreated sections of the local forest. Actual data from these trips is shown below. Consider your answer above from question 2. Now that you have spent more time and collected quantitative data in the forest plot, do you think this section of forest has previously received a restoration treatment? Which data/observations did you collect today that are consistent with your answer? Which are not? Tree diameters (cm) Treatment Total # trees 1 2 3 4 5 6 7 8 9 10 Average Unrestored forest 75 25 5 23 1 31 15 17 8 14 18 15.7 Restored forest 25 40 48 40 36 20 32 54 51 43 35 39.9 Transect ground cover data (%) Unrestored Forest Trees Grass Forbs Shrubs Bare ground Rock Litter Total Canopy Cover Litter depth (cm) Average 0 25 0 0 18.3 0 56.6 100% 70.8 3 Transect ground cover data (%) Restored Forest Trees Grass Forbs Shrubs Bare ground Rock Litter Total Canopy Cover Litter depth (cm) Average 0 22.5 13.3 0 4.2 7.5 52.5 100% 21.6 0.42 7

QUESTION 7 (2 points): You’ve now used two different methods to characterize ground cover of a field site. Compare the method used today (the quadrat method) with the method used in a previous lab at Sinclair Wash (the point transect method) last week. Which do you think is more accurate? Which is more subjective? Exercise 3: Determining the Age of Trees In order to understand the structure of a forest, we need to know more than just the size and number of the trees. It is also important to know something about the age of the trees. In this exercise, your instructor will show you how to determine the age of trees. QUESTION 8 (2 points): Some students conclude that the age of a tree is directly related to its size. Why might this not be the case? Forest Restoration Lab References Cited: Cooper, C. F. 1960. Changes in vegetation, structure, and growth of southwestern pine forests since white settlement. Ecological Monographs 30(2): 129-164. Covington, W.W., P.Z. Fulé, M.M. Moore, S.C. Hart, T.E. Kolb, J.N. Mast, S.S. Sackett, and M.R. Wagner. 1997. Restoration of ecosystem health in southwestern ponderosa pine forests. Journal of Forestry 95(4): 23–29. Fort Valley Experimental Forest. 2010. Fort Valley Experimental Forest: Where Forest Service Research Began. http://www.rmrs.nau.edu/fortvalley/ Accessed 01-12-10 Fulé et al. 2001. Measuring Forest Restoration Effectiveness in Reducing Hazardous Fuels. Journal of Forestry 99 (11): 24-29. Hobbs, R.J. and D.A. Norton. 1996. Towards a conceptual framework for restoration ecology. Restoration Ecology 4(2): 93-110. Kilgore, B. M. 1981. Fire in ecosystem distribution and structure: western forests and scrublands. In: H.A. Mooney, T. M. Bonnicksen, N. L. Christensen, J. E. Lotan, and W. A. Reiners, technical coordinators. Proceedings of the conference: Fire regimes and ecosystem properties. Gen. Tech. Rep. WO-26. Washington, DC: Forest Service, U.S. Department of Agriculture; 58-89. Lewis, H.T. 1985. Why Indians burned: specific versus general reasons. In: Lotan, J.E. et al., technical coordinators. Proceedings—Symposium and Workshop on Wilderness Fire; 15–18 November 1983; Missoula, MT . Gen. Tech. Rep. INT-GTR-182.: US Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station, Ogden, UT, pp. 75–80. Mooney, H.A., T. M. Bonnicksen, N. L. Christensen, J. E. Lotan, and W. A. Reiners. 1986. Proceedings of the conference: Fire regimes and ecosystem properties. Gen. Tech. Rep. WO-26. Washington, DC: Forest Service, U.S. Department of Agriculture. Parsons, D.J., D.M. Graber, J.K. Agee, and J.W. van Wagtendonk. 1986. Natural fire management in national parks. Environmental Management . 10(1): 21-24. 8