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Methods in Forest Canopy Research

Margaret (Meg) D. Lowman
Timothy D. Schowalter
Jerry F. Franklin
Copyright Date: 2012
Edition: 1
Pages: 240
https://www.jstor.org/stable/10.1525/j.ctt1ppttg
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  • Book Info
    Methods in Forest Canopy Research
    Book Description:

    Poised between soil and sky, forest canopies represent a critical point of exchange between the atmosphere and the earth, yet until recently, they remained a largely unexplored frontier. For a long time, problems with access and the lack of tools and methods suitable for monitoring these complex bioscapes made canopy analysis extremely difficult. Fortunately, canopy research has advanced dramatically in recent decades.Methods in Forest Canopy Researchis a comprehensive overview of these developments for explorers of this astonishing environment. The authors describe methods for reaching the canopy and the best ways to measure how the canopy, atmosphere, and forest floor interact. They address how to replicate experiments in challenging environments and lay the groundwork for creating standardized measurements in the canopy-essential tools for for understanding our changing world.

    eISBN: 978-0-520-95392-5
    Subjects: Ecology & Evolutionary Biology

Table of Contents

  1. Front Matter
    (pp. i-iv)
  2. Table of Contents
    (pp. v-vi)
  3. CONTRIBUTORS TO TEXT BOXES
    (pp. vii-viii)
  4. PROLOGUE
    (pp. ix-xii)

    The call of “timber” rang out in the forest as the feller completed his back cut and the immense old-growth Douglas-fir tree began its fall to the ground. Branches, tops, and all matter of organic material and dust filled the air as the tree fell and then burst into hundreds of pieces as it crashed onto the ground. After material had stopped falling, Dr. William Denison, an observer and professor in the Botany and Plant Pathology Department at Oregon State University, began working his way through the debris, shaking his head and despairing of any possibility of reconstructing either the...

  5. PREFACE
    (pp. xiii-xvi)
  6. ACKNOWLEDGMENTS
    (pp. xvii-xviii)
  7. 1 SETTING THE STAGE: Canopy Research Emerges as a Component of Forest Science
    (pp. 1-10)

    Our ancestors were tree dwellers. Throughout human history, people have taken to the trees as safe havens, sites of special spiritual connection, and cornucopias for food, medicine, materials, and productivity (reviewed in Lowman 1999; Nadkarni 2008). In many tropical forest regions, indigenous people rely on forests for their livelihoods. Increasingly on a global scale, people and governments are beginning to recognize the importance of ecosystem services provided by forests, which link directly to human health (Perrings et al. 2010). Such benefits include medicine, food, shade, building materials, gas exchange capabilities, energy production, carbon storage, genetic libraries, water cycles, and spiritual/cultural...

  8. 2 FOREST TYPES AND SITE CHARACTERISTICS
    (pp. 11-26)

    Forests are ecosystems characterized by dominance of long-lived woody plant species. Forests originally covered an estimated 50 percent of the Earth’s ice-free land surface, but anthropogenic deforestation has reduced this area significantly. The world’s forest cover has been cleared to about half of its historic extent (Matthews and Hammond 1999; Myers 1999; Perry et al. 2008; FAO 2001; Waring and Running 2007; reviewed September 2010 inhttp://www.economist.com/specialreports). Despite losses, humans continue to depend on forests for a variety of ecosystem services, including wood for building material and fuel, food from plants and associated animals, fresh water, cultural and recreational uses...

  9. 3 CANOPY ACCESS METHODS: Making It Possible to Study the Upper Reaches of Forests Accurately and Safely
    (pp. 27-48)

    The first explorers and scientists who accessed tree canopies found a new world of discovery and inspiration. E.O. Wilson called it “the last frontier” of biological research on the planet (Wilson 1992). Andrew Mitchell referred to its invisible inhabitants as “a world I could only dream of ” (Mitchell 2001). Tom Lovejoy confessed that “the canopy rendered me the biologist’s equivalent of Tantalus from the very outside” (Lovejoy 1995). Steve Sutton compared it to “Alice grows up,” as canopy science moves from a sense of wonder to a reality of hypotheses (Sutton 2001). Nalini Nadkarni exclaimed about “tree climbing for...

  10. 4 FOREST STRUCTURE AND SAMPLING UNITS
    (pp. 49-66)

    Canopy structure reflects the three-dimensional framework of boles and branches and the distribution of foliage that represent the engine for capture and processing of energy and atmospheric nutrients, processes fundamental to sustainability of forest ecosystems and the services they provide. Furthermore, canopy structure establishes the framework of support and resources for associated canopy flora and fauna, as well as the template of sample units for canopy research. Canopy structure determines rates and pathways of fluxes of carbon, nutrients, and organic material from the canopy to the atmosphere, forest floor, and associated stream systems. Consequently, adequate representation of forest structure is...

  11. 5 CANOPY CONDITIONS, BIOTA, AND PROCESSES
    (pp. 67-108)

    Forest canopies present particular challenges with respect to sampling organisms. Collecting data on abundance or effects of organisms in forest canopies requires physical access, the ability to secure and monitor sampling equipment placed in the canopy, or remote-sensing capabilities. The difficulty of accessing canopy units for replicated sampling has been a major impediment to canopy study and has generated much of the creativity in canopy access methods described in Chapter 4. Taller or denser canopies require different sampling approaches than shorter or sparser canopies.

    Sampling methods must be selected with respect to experimental objectives, safe and reliable access methods, and...

  12. 6 CANOPY-ATMOSPHERE INTERACTIONS
    (pp. 109-130)

    Forest canopies interact with the atmosphere in a number of ways that affect local and global climate and exchange of carbon and other materials. Forest canopies buffer terrestrial surfaces from extreme variation in temperature, precipitation, and wind, moderating conditions for associated organisms and ecological processes. The degree of buffering depends on the extent of canopy cover, depth, and complexity. Exchange of materials, especially water, occurs through foliage stomata, influencing local humidity and precipitation patterns. Deforestation has disrupted canopy-atmosphere interactions, exposing the land surface to greater variation in regional temperature, precipitation, and wind speed (Foley et al. 2003).

    These interactions can...

  13. 7 MEASURING CANOPY-FOREST FLOOR INTERACTIONS
    (pp. 131-152)

    Forest canopies significantly affect, and are affected by, conditions on the forest floor. The canopy intercepts light, water, and airflow, modifying forest floor temperature and penetration of water and nutrients to the forest floor, and thereby reducing leaching, erosion, and export of sediment and nutrients from the forest. Canopy materials are exchanged with the geosphere through uptake of water and nutrients from the soil, translocation of carbohydrates to the rhizosphere, and turnover of plant and animal tissues and nutrients to the forest floor via throughfall and litterfall (Pendall et al. 2004; Prescott 2002). Exogenous factors, such as environmental changes and...

  14. 8 TREETOPS AT RISK? Engaging the Canopy Toolkit in Forest Conservation
    (pp. 153-168)

    Despite extensive scientific research invested in tropical forests and their canopies during the past few decades, deforestation is increasing and rates of degradation continue to accelerate worldwide (Curran et al. 2004; Laurance and Perez 2006; Lowman 2009b). In some cases, the methods to measure forest degradation are not adequate to accurately quantify changes in canopy cover, especially with selective cutting or replacement of native stands with tree plantations (e.g., Puyravaud et al. 2010). Other studies have advocated efforts to save some tropical rain forests, but “we do not have to try to save every bit of it” (Janzen 2010)....

  15. 9 CONCLUSIONS AND RECOMMENDATIONS
    (pp. 169-174)

    Canopy science has advanced greatly from its early days of individual researchers climbing into accessible trees using ropes or ladders and collecting what could be reached or using binoculars to observe more distant objects. Today we have a variety of canopy access methods and sophisticated measuring devices that can record continuously by means of solar battery power. Canopies can now be observed remotely, at a global scale, using satellite imagery. However, there are a number of challenges remaining:

    1. Scaling of data from individual leaves to regional canopies, necessary to validate and correlate remotely sensed fluxes with more directly measured...

  16. REFERENCES
    (pp. 175-204)
  17. AUTHOR INDEX
    (pp. 205-209)
  18. SUBJECT INDEX
    (pp. 210-221)
  19. Back Matter
    (pp. 222-222)