forest zoning on private lands : reconciling conservation

WINTER 2013 PROGRÈS FOREST I ER - SPEC IAL ED IT ION

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Forest zoning on private lands :

reconciling conservation, restoration and production

Forest zoning (or Triad) is an interesting forest management concept because it simultaneously aims at conserving forest ecosystems (much more than only trees), extensive ecosystemic forest management, as well as intensive management (increased production). These three types of forest management are assigned to specific zones in a defined land area. This type of forest zoning has the potential to considerably reduce the conflicts between the various users of the forest.

BY BENOIT TRUAX, Ph.D., AND DANIEL GAGNON, Ph.D.

The perception of forest management has changed greatly for the private land owners of southern Quebec, where notions of conservation and restoration of the forest ecosystem are part and parcel of forest certification. However, there are currently few concrete examples of applications of forest zoning for the private land owners of the province. Forest zoning is a concept initially developed for the large forest domains of the north eastern USA and of the west coast of North America. In Quebec, the only information available on forest zoning comes mainly from large and more northern public forest areas (La Mauricie and Abitibi regions), a far different context of that of southern Quebec, with its high biodiversity forests, dominated by valuable hardwoods, and mostly privately owned. It is however possible to apply the Triad concept on a smaller scale on private lands of southern Quebec, where very high yields of wood volume on small areas allow other areas to be freed for conservation, as well as the restoration of degraded or impoverished forest ecosystems.

LAND-USE PLANNING

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FEUILLUSChênes, érables, frênes, noyers, tilleuls.CONIFÈRESÉpinettes, mélèzes, pins, cèdres,pruches, sapins.PLANTS EN CONTENANTPour haies brise-vent, naturalisation,reboisement, stabilisation des rives.PLANTES pour naturalisation.

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P É P I N I È R E

The example of the Saint-Benoît-du-Lac municipalityOur research plantations for restoring degraded forests (oak planted under partial forest canopy) were established in 1991 on a small area of this municipality. Although this oak enrichment experiment proved to be a success after 20 years, it was however necessary to obtain an overall and detailed picture of the forest and agricultural zones within the entire municipality. This municipality of 216 hectares (ha) has 15 ha of forests, 45 ha of cultivated fields, 5.5 ha of abandoned agricultural fields and apple orchards, 8.5 ha of producing apple orchards, and the Abbey itself (buildings, roads and parking lots) occupies 7 ha. The Benedictine Community acquired this property in 1912, at a period when forest harvesting and agriculture were already well-established activities in this part of the Eastern Townships. During the following 100 years, human activity has greatly modified the municipality’s landscape through forest harvesting and agricultural expansion. Forest harvesting has generated a multitude of types of forest stands, ranging from old sugar maple stands to very young forests poor in species, consisting mostly of intolerant hardwoods (birches, poplars), in all a situation very similar to most of the current landscape of the entire Eastern Townships. It is in this context that a forest zoning model was used to delimit three zones in the Saint-Benoît-du-Lac municipality: a forest conservation zone, a forest ecosystemic management zone (including forest restoration) and an intensive management zone, with the objective of achieving increased wood production on a very small area (see the inserts about these three types of zones).

Detailed analysis to determine zones of conservation, ecosystemic management and intensive productionFollowing a detailed study of eco-forest maps and aerial photos, and using a geographical information system (GIS), a preliminary zoning of the Saint-Benoît-du-Lac municipality was produced to define three zones: one of conservation, one of ecosystemic forest management (including restoration) and one of increased production (of wood and biomass). Among the forested areas of the municipality, we determined which parts could be assigned to conservation and which parts could be assigned to ecosystemic forest management, including, among other options, the restoration of certain tree species historically more abundant in the landscape, such as red oak and white pine.

Sampling forest standsDuring summer 2010, 71 permanent plots of 400 m2 each were established within the entire forested area, in order to make a detailed ecological survey of the different forest communities of the property. Several ecological variables were measured (elevation, slope aspect and angle, topography, soil drainage class and percent surface rock cover), as well as the height of the forest canopy in each plot. Each tree larger than 1 cm diameter at breast height (DBH) was identified to species, counted and had its DBH measured. Increment cores were taken from two to three of the largest trees, presumably the oldest (hemlock, maple, ash, etc.), in order to determine their age and their growth over the last five years. A list of understory plant

species (herbs and small shrubs) was made. Particular attention was given to record the presence of stumps (from the last harvest) and of dead tree trunks on the ground (length and diameter recorded). Finally, signs of animal presence in the plots were recorded (feces, bones, rubbings on trees, dens). Afterwards, ordination analyses were done to identify the various types of forest communities found on the property of the Saint-Benoît-du-Lac Abbey, and to determine which ecological factors were associated with their distribution.

ConservationAfter the analysis of the vegetation ordinations, it was possible to associate almost all of the sampled plots to a particular type of forest community (Figure 1). Indeed, it is possible to delimit areas of old forests from those of young forests. Old forests are found in areas where agriculture was never developed (the soil was too stony), whereas the young forest of Saint-Benoît-du-Lac are the result of the abandonment of agriculture, about 50 years ago, and are usually of poor quality. In spite of forest harvesting since the founding of the Abbey in 1912, several plots sampled had clear attributes of old-growth forests, such as the hemlock, sugar maple and yellow birch stands, with trees older than 255 years. In order to guide the inclusion of parts of the forest in the forest conservation zone, we used seven criteria of conservation value: 1) corridor that includes a stream; 2) connection with neighbouring forests (outside of the property); 3) old forests (more than 100 years old); 4) abundant dead wood on the forest floor; 5) abundant

Figure 1. Forest zoning scenario at the Saint-Benoît-du-Lac municipality (conservation zone 25 % of forested area; ecosystemic/restoration forest management zone; intensive plantation production zone).

Ecosystemic management : 113 ha

Source : Ministère des Ressources naturelles, Québec.

Conservation 25 % 37.1 haRestoration 24.2 ha

Production 3.46 ha

Undetermined

White ash stands

Maple - white ash stands

Maple - beech stands

Large-tooth aspen stands

Grey birch - balsam poplar - elm stands

Cedar stands

Balsam fir stands

White pine stands

Hemlock - maple stands

Hemlock - yellow birch stands

Hemlock - maple - yellow birch stands


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presence of large snags and hollow trees; 6) presence of rare, vulnerable or threatened plants; 7) presence of animals or of signs of their presence (mammals, birds, reptiles, amphibians, fish). Each plot was attributed a conservation value based on these seven criteria. Fixing the boundaries of the conservation zone was somewhat simplified by the presence of two major streams flowing across the Saint-Benoît-du-Lac municipality and into Lake Memphrémagog. The forest zone surrounding these streams is directly connected to forests on neighbouring properties, facilitating the movements of animals.

Choosing a forest zoning scenario for Saint-Benoît-du-LacFollowing a detailed analysis of the sampled forest plots, using the criteria for conservation value, determining their potential for production or forest restoration, as well as soil analyses of the agricultural zone, we proposed a forest zoning scenario for this privately owned land of southern Quebec (Figure 1). This scenario may certainly be modified with the acquisition of new data, such as on wildlife for example. For the forest conservation zone, we propose that it be created on 25 % of the forested area, or approximately 37 ha, mainly as a large forested corridor encompassing one of the streams of the municipality. This corridor contains the oldest forests on the property. We also delimited a second area, smaller than the first area and separate from it. This smaller area has populations of several rare plant species, as well as a large number of snags and large cavity trees that are very important resources for wildlife. The remainder of the forested area, approximately 113 ha, was included in the ecosystemic forest management zone. Tree harvesting is still possible in 80 % (89 ha) of this zone, as long as the principles of ecosystemic forest management are respected (see the insert). On the rest of its area (24 ha), the ecosystemic forest management zone is composed of young forests resulting from agricultural abandonment (crops, orchards) and of degraded cedar swamps. These young forests on former agricultural land are dominated by grey birch, paper birch and poplars. This is an environment that is particularly favourable for under canopy planting of red oak and white pine, in agreement with an

ecosystemic forest management principle that we need to restore species within a landscape where they were once more abundant. Finally, for the intensive management zone, located in part in the agricultural zone and in part in recently abandoned field edges (old fields), approximately 3.5 ha have been planted with hybrid poplars for biomass production. The yield from this small zone of intensive production is exactly the same as that of the total yield of the natural forest (on an annual basis) in the conservation zone. This comparison is a particularly convincing illustration of the enormous leverage effect for conservation that is generated by this increased wood production on agricultural soils. It is 37 ha of forest, with high conservation value, that has its entire annual wood production compensated by only 3.5 ha of hybrid poplar plantations. This is the key to the forest zoning concept. The conservation and ecosystemic forest management zones are “subsidised” by the increased production of the intensive management zone. Without this increased production, the promise of gains in areas of conservation and sustainable forest management, using ecosystemic management principles, will be difficult to achieve.

ConclusionThis study has shown that it is entirely possible to propose a realistic forest zoning scenario, within inhabited and privately owned lands in southern Quebec, allowing a much more harmonious co-existence of forest mana-gement and forest conservation. We believe that this kind of scenario could help to decrease the conflicts between the various forest users. However, this research project is not completed. We still need to test the wider applicability of this zoning model by including several types of private properties, from landscapes that are predominately agricultural, mainly in the Montérégie and Centre-du-Québec regions, to landscapes that are predominately forested, such as at higher elevation towards the Appalachians. Also, where the individual properties are much smaller in size than Saint-Benoît-du-Lac (216 ha), areas encompassing several adjacent properties will need to be considered as a whole. In these multi-owner areas, we are convinced that the objective of identifying zones of conservation, ecosystemic management and intensive management can also be attained. The diversity in personal

objectives of the various land owners may then become an asset, instead of an obstacle.

Acknowledgements

We sincerely thank the Benedictine Community of Saint-Benoît-du-Lac for having allowed this project to be carried out on their property and for having provided their support to our research projects for over 20 years. We wish to also thank the Ministère des Ressources naturelles du Québec, Natural Resources Canada and the Programme de mise en valeur des ressources naturelles Volet II for the funding received, as well as many donors: Trees Canada, Novabus, Ski Bromont, Association forestière des Cantons-de-l’Est and Mr. P. Kilburn. Finally, we want to thank our research professional (F. Lambert), our field technician (J. Lemelin), our interns and students (K. Boothroyd-Roberts, M.A. Petrin, A. Richard, A. Laflamme, J. Fortier, D. Pageault), and our volunteers (L. Godbout, J.D. Careau, Y. Daigle, S. Wood-Gagnon, S. Gendron).


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Photographs by Daniel Gagnon and Lionel Godbout

Hybrid poplar plantation on a fertile abandoned field at Bedford, where the average yield obtained after 8 years was 23 m3/ha/year for a density of 833 stems/ha.

Hybrid poplar plantation (for producing biomass for heating) near the edges of cultivated fields at Saint-Benoît-du-Lac. The trees in the photo are nearing the end of their 1st year of growth.

Intensive management is probably the most limiting element of a forest zoning project (Triad), no matter whether it occurs on public or private land. The higher the yield obtained in the intensive management zone, the larger the area that can be allocated to the forest conservation and ecosystemic forest management zones. It is therefore critical to obtain realistic and validated yield data for the region where the application of the forest zoning is planned. This is needed in order to reduce as much as possible the errors due to the possibility effect over the long term. This would decrease the advantages of the zoning system. Our research projects, since May 2000, with hybrid poplars planted on old-fields and as riparian buffers in agricultural areas of southern Quebec, have led to the establishment of a target yield of 30 cubic metres/hectare/year, or 13 dry metric tonnes/hectare/year, for a rotation of less than 10 years (see the references to papers by Truax and collaborators). This target yield was established using a multiple regression model derived from the analysis of 120 hybrid poplar trees harvested after 8 years of growth (in 2007), in eight experimental plantations distributed along a climate and soil fertility gradient, from Bedford (St. Lawrence lowlands) to Lac-Mégantic (Appalachians), where three factors explain poplar yield for southern Quebec. These are, in order of decreasing importance: 1) the elevation (or climate), 2) available soil phosphorus, 3) soil calcium. Therefore, for our forest zoning project at Saint-Benoît-du-Lac, it was possible to predict hybrid poplar yield by obtaining the elevation (using a GPS), using the results of soil analyses for phosphorus and calcium, and account for a higher density of planted trees (1666 stems/ha). Furthermore, we monitor the annual growth of 2000 hybrid poplars planted in May 2011 on the Abbey property, which will validate our predicted yield results and our zoning scenario. Finally, it is important to add that these high yield plantations also have several additional benefits, one of which is to supply biomass for heating the Abbey, since the monastery has recently converted its heating plant to wood burning energy. The hybrid poplar plantations also provide ecosystem services, such as sequestration of carbon (CO2) and excess soil nutrients from agricultural fertilizers, thus reducing non-point source water pollution.

Intensive management and increased wood production zone

Références Truax, B., Gagnon, D., Fortier, J. and Lambert, F. 2012. Yield in 8 year-old

hybrid poplar plantations on abandoned farmland along climatic and soil fertility gradients. Forest Ecology and Management 267: 228-239.

Truax, B., Lambert, F. and Gagnon, D. 2000. Herbicide-free plantations of

oaks and ashes along a gradient of open to forested mesic environments. Forest Ecology and Management 137: 155-169.

To find out moreBenoit Truax, Ph.D., Director General, Eastern Townships Forest Research Trust, tel. 819-821-8377, [email protected], www.frfce.qc.caDaniel Gagnon, Ph.D., Dean, Faculty of Science, University of Regina, CEF-UQAM, [email protected]


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Ecosystemic forest management zone

What is ecosystemic forest management? “We must pay equal attention to what we are leaving as to what we are harvesting” is a simple way of encapsulating this new forest management concept, now officially part of the forest policy of Quebec. The objectives of ecosystemic forest management are to maintain the biodiversity and the productivity of forest ecosystems, over the long term, at the landscape scale. This way of seeing the forest as an ecosystem is not new. A forest does not only have trees, but also animals, and not only those that we hunt, but also shrews, flying squirrels, bats, snakes, salamanders, insects and all kinds of invertebrates. There are also the plants we find in the forest understory (shrubs, herbs, mosses, liverworts and lichens), the mushrooms (or fungi) and microorganisms, such as bacteria. We now know that this impressive biodiversity has a key role in maintaining the long term productivity of ecosystems. In order to maintain this biodiversity, when a forest is exploited, we must ensure that we leave behind enough “ecological legacies”. This “inheritance” that we want to give to the future forest can be of multiple types, such as large live trees (which will become the dead or hollow trees of the future forest), tree seedlings and saplings, litter and humus layers (with dormant seeds and underground plant parts), standing dead trees (snags), dead trees on the ground, etc. Sometimes the current forest is in a degraded state because of repeated harvests, or poor in species because it is very young and originating from agricultural abandonment. In both cases certain species of trees or understory plants, once present in the past, are no longer part of the forest. In order to reintroduce these species with important ecological roles, we must do restoration plantations, one of the

many aspects of ecosystemic management. This is particularly important in southern Quebec, where the forest has been exploited and gradually transformed into agricultural land for over 200 years. In 1991, we did such restoration work at Saint-Benoît-du-Lac, under the canopy of young forests resulting from agricultural abandonment, by planting red oak, bur oak, white ash and red ash (see the references to papers by Truax and collaborators). In May 2012, we extended these restoration plantations to a much larger

Restoration plantation of red oak and white pine, under the canopy of a young grey birch forest, in May 2012 at Saint-Benoît-du-Lac.


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The modern forest manager considers that conservation is an essential part of achieving the sustainable management of forest resources, because biodiversity has a vital role to play in maintaining long term forest productivity. Conservation zones, of sufficient size, are therefore essential within exploited forest areas. What are the reasons for having conservation zones? First, a conservation zone will serve as a baseline for the parts of the forest that are being exploited. It is a “control”, a forest undisturbed by human activity, which will allow us to answer questions that arise in the future. For example, why does a plant or animal species decline in exploited forest areas, and not in conservation zones? Also, how does the forest ecosystem function under natural conditions? How does it recycle nutrients among its many compartments (litter, humus, soil, living plant biomass, dead plant biomass, invertebrates, fungi, microorganisms)? Can we harvest all of the forest biomass (tree trunks and branches, dead wood, litter) and export it away from harvesting sites, without threatening the future productivity of the ecosystem? Also, although ecosystemic forest management aims at maintaining biodiversity, there are a certain number of forest species that cannot adapt to disturbances and cannot survive in exploited areas. For example, there are species that can only be found in old forests, or mostly in them. Many bird and mammal species nest or take shelter in the cavities provided by large trees or large hollow trees. These large trees are absent in young forests. A particularly striking example comes from Europe, where forests have been exploited for centuries. All of the trees were harvested while alive, without allowing any to die naturally and create snags or dead wood on the ground. This was once a sign of good management, where nothing was “wasted”. The result of this is that there are now several species of fungi (mushrooms) that are threatened in Europe, simply because there is no dead wood on the forest floor. Why complain? Because fungi are important decomposers of litter and because they play a major role in recycling nutrients in forest ecosystems. Fungi form associations (mycorhizas) with tree roots,

Hemlock, sugar maple and yellow birch forest, over 255 years old, at Saint-Benoît-du-Lac.

Dead wood, abundant in old forests, plays a vital role in forest ecosystem biodiversity and productivity.

WANTED: Private forest owners and agricultural producersThe Eastern Townships Forest Research Trust is seeking properties that may be suitable for pursuing its forest zoning project in summer 2013. We are developing a list of potential properties to include in our study and we are requesting the assistance of private land owners (forest and farmland) interested in participating. Please contact Mr. Benoit Truax by phone at 819-821-8377 or by email at [email protected] in order to learn more about this major project, covering the entire Eastern Townships region.

area and to a larger number of sites within the proposed ecosystemic management zone, by planting red oak, white pine, black walnut and hickory. In order to see if deer browsing would affect the success of these plantations, half of the planted saplings were protected using “K-type” protection sleeves, developed and tested over 10 years by Mr. Peter Kilburn, one of the pioneers of hardwood reforestation in the Eastern Townships.

Forest conservation zone

helping trees capture soil nutrients, particularly phosphorus. To maintain long term forest ecosystem productivity, we require fungi, and they themselves require dead wood. The forests in conservation zones are essential to help us understand the functioning of forest ecosystems, because we still have a lot of things to learn.

The result at 18 years of a restoration plantation of red oak under the canopy of a young trembling aspen forest at Saint-Benoît-du-Lac.


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forest zoning on private lands : reconciling conservation

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