Since May 2014, Pehuén Forest and the Laboratory of Biodiversity and Canopy Ecology of the Institute for Conservation, Biodiversity and Territory of the Faculty of Forest Science of the Universidad Austral of Chile, joined in a collaboration agreement in order to conduct long-term monitoring and scientific research in different biological systems found inside the property.
Documenting biodiversity and the effects of past exploitations to understand the natural regeneration mechanisms of a forest are the basic objectives of the team of scientists composed by Iván Díaz, Daniela Mellado and Javier Godoy, who since May 2014 have been researching in Pehuén Forest. The trees are the central figure of the work, because they are the organisms that structure the forests.
Considering the tree as a broad subject of study has been one of the differentiating foci of research. In order to study the trees, the Laboratory of Biodiversity and Canopy Ecology (LabDosel) utilizes ropes and arborist techniques to reach the highest parts of the canopy, an area that is commonly referred to as “forest canopy”. LabDosel is the first laboratory for these studies in Chile, and Pehuén Forest has become the main study site for canopy practices in the country.
The old trees form environments with great biodiversity. In Bosque Pehuén, the first study in Chile of the epiphytic biodiversity (plants that live above the trees) was developed in the Andean forests of coigüe trees (Nothofagus dombeyi). The results show an abundance of mosses, with 17 species living in the canopy. This study created the first collection of canopy mosses in Chile, which was donated to the National Museum of Natural History in Santiago. Other unpublished fauna records were obtained in the canopy, which evidenced that treetops are in fact permanent habitats for animals such as the lizard (Liolaemus pictus) and the chick spider (Grammostola rosea).
The first microclimatic study of the canopy in Chile was also developed here in Pehuén Forest, and one of the first in the world, with temperature and humidity sensors placed between zero to 24 meters high, in a vertical grid within the forest. The results show that the canopies are more humid than previously assumed, and are warmer than the forest floor. This combination between temperature and humidity contributes to explaining the presence of biodiversity found at these levels, and reveals tree-tops as a favorable environment for the development of epiphytic plants. More than 80% of invertebrates, more than 50% of birds and up to 50% of vascular plants inhabit the canopy.
Another focus of research is the regeneration of the forest. Due to its forestry potential, the property was heavily cleared in the 1970s, hence regenerating forests are observed on a considerable area of the property. For this study, six permanent plots were monitored on a successional gradient, which means that the plots cover the entire range of degrees of human intervention, from highly disturbed systems such as shrubs and grasslands to almost pristine systems such as ancient forests.
Dead woody debris or fallen logs were observed in a different state of decomposition. The amount of dead woody debris recorded in Pehuén Forest plots is within the highest known ranges of dead woody material in the world. This is the habitat where the new forest trees develop. Dead woody debris, together with standing dead trees, are called biological legacies. Studies in Pehuén Forest show that the presence of these legacies in the intervened forests is key for the presence of birds. Thus, these studies suggest a new model for native forest management that would favor regeneration.
Biodiversity monitoring of the plots, together with other data and modeling in the laboratory, served to create, in 2016, a new zoning of Pehuén Forest according to the protection and possible renewal of each hectare. This knowledge can be applied to take conservation measures in other parks, estates or territories that require it.
On June 6, we signed a collaboration agreement between the Fundación Mar Adentro, manager of the Parque Bosque Pehuén and the Laboratory of Canopy Biodiversity and Ecology of the Institute for Conservation, Biodiversity and Territory of the Faculty of Forest Sciences and Natural Resources of the Universidad Austral de Chile, with the aim of developing scientific research in the Park. In this way we started to implement our Research Program. This work will last from June 2014 to May 2015.
Protected wilderness areas, both public and private, are essential for the conservation of biodiversity and ecosystemic services, such as for instance, water supply. For effective conservation in protected areas, we need to know the biodiversity of species within the area, where they are located, how they change over time and quantify the ecosystemic services provided. Numerous experiences have shown that long-term monitoring has been essential to detect changes in population and ecosystems, has provided mitigation measures, has allowed assessing if conservation actions have been successful and has provided clear guidelines for the restoration of populations and ecosystems. In Chile, these efforts are just starting with the first network of long-term study sites created by the IEB (Institute of Ecology and Biodiversity-Chile), a network which is under development.
In order to monitor biodiversity, some authors (Franklin and Noss) have developed an analysis scheme that goes beyond species. In this scheme, large trees, for instance, generate structures that change the temperature, light and humidity conditions of the site they inhabit, and are habitats for a great variety of other organisms, such as the plants that grow above these trees (known as “epiphyte” plants). This link between the structure and composition of species may have a third link, which are the functions they perform, such as nutrient fixation, recycling, photosynthesis, pollination, and water harvesting, among other functions.
The entire vertical profile of trees, from a few meters above the ground to the highest point is known as the “canopy” of the forest. This layer is where the biological diversity of forests is concentrated. For example, over 80% of invertebrates, more than 50% of birds and up to 50% of vascular plants inhabit the treetops; however, this is a subject that has been hardly explored. In Chile, the first canopy study was done on larch (Fitzroya cupressoides) forests by Clement et al. (2001), during a visit to the Parque Nacional Alerce Andino. However, this pioneer study was an isolated effort, describing the flora and structure of the larch canopy.
Subsequent studies have been made by the Laboratory of Canopy Biodiversity and Ecology of the Institute for Conservation, Biodiversity and Territory of the Faculty of Forest Sciences and Natural Resources of the Universidad Austral de Chile, in forests of Chiloé and more recently in forests of Valdivia. These last studies have shown that trees such as the Ulmo (Eucryphia cordifolia) host 21 species of vascular epiphyte plants that are essential to maintaining an enormous biodiversity of insects in the canopy which contribute to the food chain, increasing the abundance of birds.
In Chile there is already information about the canopy’s importance, but said information is still partial, concentrated on coastal forests and two species of trees. In this sense, the research that will be conducted in the Pehuén Forest incorporates old Andean forests and forests in different successional post-human disturbance states. Thus, highly relevant information could be generated for the conservation and management of the native forest, such as:
- Document the current and not documented biodiversity in the canopy of Andean forests,
- Understand the effects of past exploitation on biodiversity,
- Document how this biodiversity changes over time and the forest’s development, and
- Define some of its functions, such as rainwater harvesting, fog and carbon in forests.
In addition, permanent monitoring plots can be used for educational and demonstration purposes in which visual material can be developed together with interpretive trails linked to the research therein conducted.
Therefore, the research to be conducted within the framework of the collaboration agreement aims to establish a long-term monitoring program for the study of the forest’s biodiversity and its functions, based on a series of specific short-term questions, such as:
- What is the diversity of epiphytes (lichens, moss and vascular plants) in the canopy of the Andean forests of the Bosque Pehuén?
- How does the plant biodiversity change in a successional gradient, product of human intervention in the Bosque Pehuén?
- How does biodiversity change in a successional gradient between the forest’s ground and canopy?
- What is the contribution of this knowledge to the management and conservation of the forest?
Through this research we want to establish in the Bosque Pehuén the first program in Chile for the long-term study and monitoring of the canopy’s biodiversity by setting up five permanent plots (50×20 m) in a successional gradient, from areas of old forests to secondary forests of different ages. The wealth of plants present at the forest’s ground level will be recorded and the amount of epiphytes on the vertical profile of the trees will be assessed. The old forest plot will be defined as a permanent plot for the canopy study, and the features of each tree within it will be measured and the tip of its highest living branch will be tagged to know how much it grows each year. Temperature and humidity sensors will also be placed and they will allow characterizing the microclimatic conditions of the canopy, unknown data in most of the world’s forests. This will provide a baseline of the wealth of species and the climatic features where they develop.
The research will enable us to know how many species there are in the canopy, how many are recognized from the ground and therefore, how many species are not recorded in the plant inventories developed from the ground. These results will also allow us to relate the wealth of species with different species of trees and the size or age of the tree. These data will provide useful information for the forest’s protection, to define management areas and to learn about the possible consequences of past exploitation on the wealth of species of the forest.
This work is a first step that will later on incorporate the study of certain environmental services such as water harvesting. Thus, the plots established at this stage will allow us to relate the wealth of plants with their ability to intercept rain and fog. Fog is an important entrance of water to the ecosystem and it is performed in the treetops, either through the tree foliage or by the species inhabiting their canopy. Understanding this process will be very important in a climate change scenario where rainfall decreases and in which fog will probably have a very strong influence in providing water.
WORK IN THE CANOPY
To access the tree canopy, professional arborist techniques of single and double rope will be used, following the materials and protocols developed by the “Tree climbing coalition” (www.treeclimbingusa.com). The trees to be climbed are large and old trees, usually with diameters of more than 50 cm and 30 m high. The climbing of these trees takes time, but with the single and double rope techniques practically any place of the canopy and tree can be reached, except for the thinner terminal branches. This will permit making a thorough sampling of the biodiversity in the canopy of this forest.
The research team is led by Dr. Iván Díaz, who has 9 years of experience climbing trees in Chile, and is a certified climber from the Institute for Tropical Ecology and Conservation ITEC (www.itec-edu.org).
As regards the laboratory, it has 4 years of experience climbing trees in Chile. The team is made up of Dr. Camila Tejo, who has 8 years of experience in climbing trees and completed her doctorate at the University of Washington studying the canopy of the forests in the US Pacific Northwest. In addition, there are the graduates from the Universidad Austral, Javier Godoy (Engineer in Conservation of Natural Resources, and currently finishing a Master of Forest Sciences); Daniela Mellado (Engineer in Conservation of Natural Resources), and Ricardo Moreno (Forestry Engineer).
For more information on the team and their work: www.doselbosquechileno.cl
GENERAL INFORMATION ON FOREST CANOPY
“The canopy consists of all the vertical profile of the forest, from two or three meters above the ground to the highest tip of the trees. This layer has been a frontier in the knowledge about forests, due to the difficult access to the treetops from the ground. Worldwide, the first studies began in the 70’s by developing specialized equipment and techniques for climbing trees. These three decades of study in the world have shown that this layer is extremely important because that is where most of the biodiversity of the world’s forests is concentrated and where essential processes such as photosynthesis and uptake of rain and fog occur (Ozzane et al. 2003). For instance, over 80% of invertebrates, more than 50% of birds and up to 50% of vascular plants inhabit the treetops (Gentry and Dodson 1987), most of which are not to be found on the ground. Every year new species are discovered in the treetops, including insects, plants and vertebrates (Ozzane et al. 2003). However, this layer remains poorly studied and its biodiversity and ecological functions are not known in many forests of the world, including Chilean forests (Zotz 2005). This knowledge is essential for forest conservation plans, since by not studying the canopy wrong steps might be taken in biodiversity conservation, particularly in a scenario of climate change. Canopy species would be the first to be affected as they are more exposed to changes in rainfall and ambient temperature (Nadkarni & Solano 2002).
In Chile, the first canopy study was performed on larch forests (Fitzroya cupressoides) by Clement et al. (2001), during a visit to the Parque Nacional Alerce Andino. However, this pioneer study was an isolated effort, describing the flora and structure of the larch canopy. Subsequent systematic studies have only been carried out by our laboratory (Díaz 2009, Díaz et al. 2010, 2012, Peña-Foxon et al. 2011) in evergreen coastal forests of Chiloé. These last studies have shown that trees such as the Ulmo (Eucryphia cordifolia) host 21 species of vascular epiphyte plants (plants that grow on the tree only using it as substratum) and have found that epiphytes are essential to maintaining an enormous biodiversity of insects in the canopy (Díaz et al. 2012) which contribute to the food chain, increasing the abundance of birds (Díaz 2009). Despite the canopy’s importance, this is still a poorly studied and very varied environment, a diversity which is generally unknown and undetectable from the ground, and therefore undervalued (Díaz et al. 2010). For example, just on two large ulmos in Chiloé 12 species of ferns of the Hymenophyllum genus were found, known as filmy ferns, which are very sensitive to moisture (Díaz et al. 2010). This is a large number of species, considering on one hand that throughout Chile 25 species are described, and on the other hand, that previous authors assumed that these ferns do not live on treetops (Parra et al. 2009). Therefore, future studies will shed more light on the wealth and importance of the species that live associated with the forest canopy”.