Managing mixed stands in plantation forestry: utopia or opportunity?

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1 Managing mixed stands in plantation forestry: utopia or opportunity? 2014 IEFC/EFIATLANTIC Annual Meeting, 29th April, Bilbao Alejandro Cantero Amiano (HAZI) & Roque Rodriguez Soalleiro (USC)

2 Backgrounds 1: Pro Silva France annual study travel in Spain: «Pinewood and mixed forests in the Center of Spain», mars 2014: visit of mixed pinea-pinaster (sandy ares near segovia), pinaster-sylvestris (Central range) and nigra-sylvestris stands(cuenca range). Traditional way of management as even-aged forest trying to simplify the composition of each compartment by having a single species is changing because of many results of research which point to an important effect of facilitation of pine seedlings by adult trees.

3 Backgrounds 2: Most research and information on mixed stands in Spain are from University of Valladolid in Palencia and from INIA in Madrid Mixtures are important given the scenario of climate change and increasing risks. Forest School in Palencia (University of Valladolid) andiniaaretheonesleadingtheresearchinthisarea

4 Backgrounds 3: Awareness of the advantages of mixed stands in different circumstances: - Protection forests under natural risks (examples as the silvicultural guides for mountain areas: Alps, Pyrenees) - Plantations where more shade tolerant species are to be promoted: conifers+beech, productive pinewoods lengthening the rotation - Production forest with lack of investments/management: natural mixtures and variety of wood products obtained after some time

5 Backgrounds 4: Some characteristics of mixed stands were/are analysed in several European projets leaded by IEFC/EFI-Atlantic: Forsee (surface changes, sustainable forest management indicators), Reinfforce (forest mensuration, growth) or Forrisk(natural risks). Several partners from Northern Spain (Hazi, USC, ) have participed in these projects. In relation to Forrisk Project, Forest ecosystems principia : heterogeneity and risks/unpredictability. So, mixed forests are the best options

6 Mixed stands and plantation forestry Plantation forestry in Northern Spain. Private owners, high productivity. -Canmixedstandshavearoletoplayinthiscontext? -Is it merely utopia in a context of reduction of active management? - Is there enough knowledge to define silvicultural guidelines to take advantage of the opportunities of mixed compositions in plantations?

7 Mixed pinewoods in the center of Spain: The mixed pinewoods visited by Pro Silva France are semi-natural forest of mountain central of Spain, derived from natural regeneration of different pine species, in areas where site conditions are variable enough to allow the presence of two or even three pine species and, more important, these forest are public and managed by the regional forest service The human activities promote these mixtures: for example, pineapinaster. Pinus pinea promoted by its fruits and Pinus pinaster by its resin.

8 Are mixed forests frequent in Spain? NFI shows that, more or less, 20% of Spanish forest surface is mixed - 30%inGalicia - 15%inBasqueCountry Don t forget that, sometimes, this amount depends on the scale of the vegetation map and on the property structure.

9 Northern Spain 1: Mixed species plantations could play a role in strictly speaking planted forests, but for the area between Galicia and the Basque Country most forest belonging to private owners or collective owners: extended use of fast growing species, mainly exotic, complete lack of consideration of mixtures in the private management of these forests. (The small share of forest managed by the regional forest services and the protected areas are somehow different). Planted chestnut Natural regeneration of maritime pine

10 Northern Spain 2: It is clear that, for example, some mixtures of maritime pine and oaks could be managed for wood production and landscaping-nature conservation, clearly with a reduction of timber production. The problem is that there are only a few examples of forest management with these goals, always from the regional forest service. In other words, and for private owners, you can be more than happy if they do any active management at all, particularly in these hard times where investments if forest tending are at the bottom of the priorities list.

11 In collaboration with Braulio Molina, Galician Forestry Association Mixed stands in Northern Spain 1: 1.Mixturesattheplotlevel Smallplotsizemakesthestructureofwholeforestveryvariedintermsofspeciesandages,buteachownerplants just one species per plot. This is particularly the case in some areas prone to planting different species. Theresultisamosaicofpureplotsossmallsize. 1 ha plot Orthophoto of agricultural and forest plantation plots near Vilalba. SIGPAC

12 2.Treebytreemixtures In collaboration with Braulio Molina, Galician Forestry Association Mixed stands in Northern Spain 2: 2.1. Derived from natural regeneration after planting. Frequent for maritime pine after pine or broadleaves plantings. Also birch regeneration after chestnut or Douglas plantings. These stands can be classified as no intended mixed stands, but with interesting silvicultural opportunities, not always considered by forest owners/managers: - Mixtures radiata + pinaster, removing progressively the lower growth and less adapted species. Problems to mechanize the tending operations(regeneration among rows of radiata pine).

13 In collaboration with Braulio Molina, Galician Forestry Association Mixed stands in Northern Spain 3: - Broadleaves regeneration improves the stem shape and branchiness of chestnut/douglas, even if growth is reduced by competition. Less need of formation prunings. - Broadleaves regeneration after radiata pine plantation. Difficulty to liberate the broadleaves from the strong pine competition Even-aged stand of Natural regeneration of maritime pine common oak and chestnut

14 Mixed stands in Northern Spain 4: 2.2. Derived from the plantation itself. With several variations In collaboration with Braulio Molina, Galician Forestry Association - Intended melange to take advantage of the soil improving or accompanying effect of broadleaves, or to increase initial density using pine seedlings. Seldom the case, difficult silviculture, need to open space for broadleaves development. - Mixture derived from the grant scheme, which promotes the use of broadleaves. If the management is not active intending to promote the broadleaves, these are usually dominated by the conifers.. - Replacement of dead trees using a different species. For example, replacing pine trees affected by Armillaria with Douglas, replacing dead chestnut seedlings with Quercus rubra. Planted maritime pine: Dominant but nor pruned, no precommercial thinning Planted birch and American oak

15 View of mixed stands by Forest Owners associations: Mixed species plantation management is difficult and nobody in providing practical guidelines. As an example, the practical silvicultural models provided by the regional government consider in most cases pure stands. Only for Prunus or Acer the initial mixture with a pine species (to densify cheaply the stand and help control the bushes) was considered. So mixed species is probably where fun stars for a silviculturist, but this only appear to affect here to the silviculturist working for the forest service, and only partially. Most trials of research institutes and Universities in Galicia are placed in pure Pinus sylvestris, Pinus radiata, Pinus pinaster, Pseudotsuga menziesii, Eucalyptus globulus, Eucalyptus nitens, Quercus robur or Betula pubescens stands. It would be interesting to establish trials or research activities to explore advantages of mixed plantings, in terms of avoiding risks, for example. Demonstration activities with private owners?

16 In collaboration with Braulio Molina, Galician Forestry Association Utopia Opportunity 1. Management more difficult 2. Need to combine species with similar growth rates and rotations 3. Easier the mixtures coniferconifer or broadleaf-broadleaf 4. Impossible for Eucalyptus in mixtures tree by tree 5. No expectations of economic profit by forest owners 6. Mixtures frequently as a result of coincidence or lack of management 1. Neccesary the study of the management in forest trials 2. Unintended mixed stands derived from natural regeneration: opportunity to keep the mixture and promote the better adapted species or the less affected by pests and diseases 3. Possibility to use broadleaves as nurse species: improvement of soil properties, accompanying effect with improvement of shape and reduction of branchiness of the main commercial species.

17 In collaboration with Froilán Sevilla, Junta de Castilla y León Mixed forests from natural regeneration: only opportunities In Northern Spain, more frequent in public forests No plantation, few investments = low cost = good rentability To have several species is a great opportunity, not a problem It s a problem if our sylviculture is based on theoric models more than on the field reality Soft and frequent interventions promote mixed forests. In this case, forest loggings include wood from several species: something more and more frequent in the future It s very interessant the conservation of natural regeneration and, if necessary, the promotion of the conditions to reach a variety of species

18 Maximum specific diversity, with 5 species: Quercus petraea, Fagus sylvatica, Sorbus aria, Sorbus torminalis and Acer campestre. This variety and shade produce good logs in the oaks. Planned thinning for fuelwood with a good price (9 euros/estéreo). The variety isn t a problem in the price; the accesibility is the main factor in this price.

19 Pinewood of P. radiata, after 3 thinnings, with a good natural regeneration of broadleaves: Quercus robur, Q. ilex, Castanea sativa, Sorbus torminalis, Sorbus aria, and some pine. The pinewood is 60 years old, but they will do another thinning to favorise this natural regeneration.

20 Conclusions about Mixed forests in Northern Spain: Facility typology A. Privateforestswithactive managementto produce wood, NOT Natura2000, with good accesibility and with population density (aged people normally): pression to plant productive species instead of broadleaves, like eucaliptus, radiata pine, conifers, B. Private forests in protected areas or with collective private property, with private management. Satisfactory accesibility, less population density. C. Collective private property forest, but managed by Administration through contracts. Good opportunity to have mixed stands, mainly after thinnings. D. Publicforest, managedbyadministration. Perfectto haveand to manage mixed stands.

21 Some Conclusions: 1. Mixed forests, mixed stands and mixed plantations have a real share in terms of forest area, even in plantation forestry regions. These forest would probably increase in the current circunstances: increasing natural risks, uncertainties in the timber market, less intensity of forest management, 2.Inanscenariooflackofactivemanagement,thefirsttargetwouldbeanactive management of the pure stands. Mixed stands are more complicated and are not well managed, with some exceptions ( ProSilva sylviculture, some specialized forest owners, public management). 3. Mixed stands offer opportunities, even in the framework of plantation forestry, but experimental plots are neccessary to provide useful information to be transfered as practical guidelines. Most information available comes from studies of evolution of permanent plots with no active treatments evaluated. Possibility for a research project? Thank you and Greetings from the European Forest City 2014