Teagasc – Response to the Forest Reproductive Material Consultation
Prepared by Dr Niall Farrelly and Oliver Sheridan
Teagasc Forestry Development Department
14th September 2015
Introduction
Teagasc welcomes this opportunity to provide input into the consultation process for Forest Reproductive Material. Teagasc has for a number of years being conducting research into tree improvement, specifically into Birch and Alder improvement conducted at our Kinsealy research centre. More recently Teagasc has been conducting research into the potential of minor conifer species and evaluating the performance of different provenances of Sitka spruce as part of the FORGEN study. In this regard we aim to highlight some information which would be useful that may serve to inform the process.
Challenges and threats to our Forest Genetic Resource
We believe that the consultation process is particularly timely given the threat posed by novel insect pest and diseases. Recently forestry options have been reduced, with the reduction in species choice for growers due to the impact of Chalara fraxineain ash, and Phytophthora ramorum in larch in Ireland. These diseases together with the potential of Dothistroma in pine, which is currently reducing species options in Scotland, may have significant implications for species choice and the vitality of Irish Forests. There is a perceivedlack of alternative species in which to replace Ash and Larch and potentially pine species and information about additional species and their growth and yield on different site types, often marginal for agriculture is limited. Other site suitable species such as Scots pine and Douglas fir for drier sites, western red cedar, western hemlock and other diverse conifers could provide diversification and provide increased resilience to the forest estate and offer options to the potential of climate change, these species could help spread the risk of a potentially fatal outbreak of pests or disease and lessen the burden on vulnerable tree species.The effect on tree species growth and productivity in response to a changing climate needs to be planned for and various species and provenances may afford tolerance to increased wetness, dryness or increased windiness, therefore knowledge about the species ecology and response to climatic stimuli and the potential for provenance selection may afford security to ensure the sustainability of the forest estate.
While the range of potential species for forestry is vast, the list of species that show commercial potential is quite limited. Outside the main commercial species of Sitka spruce, Lodgepole pine, Norway spruce, Douglas fir, etc. there are a number of issues to be addressed in order to find suitable candidate species that may show potential for Irish Forestry. Firstly sufficient quantities of material of minor conifer species is not yet available from the commercial nurseries (e.g. Grand fir, western Hemlock and western red cedar), therefore supply issues need to be addressed. Often information on the best provenance to use is limited for the more minor conifer species, this can be critical to ensure productive commercial plantations. Therefore we must source the best material to ensure that the best plants are available for planting and that a supply of material is available in order to use in the planting programmefor each given species. Gaps in the information should be addressed by further research, for example it may be prudent to concentrate efforts on five conifers with most potential and five broadleaved species, following a cost/benefit analysis. There is need to provide more information on provenance selection for more minor conifers, without this we will be faced with disappointing performance in established plantations with inferior timber products. For example provenance selection may be more important in the minor conifers than that of Sitka spruce, for example Douglas fir provenances show considerable variability in diameter for a given provenance than Sitka spruce and certain provenances of western hemlock are associated with increased fluting. While these species are already acceptable for grant aid, you can’t expect an increased uptake of minor coniferous species, without adequately addressing the provenance question. Other issues such as thelack of available plants, lack of knowledge about the species in question, poor site selection, and establishment problems can be more easily addressed. Therefore while a larger number of species would be welcomed together with timber quality characteristics desirable for the timber sector, we must combine provenance testing to ensure the most appropriate seed origins for Irish conditions.
For a number of species, western hemlock, western red cedar, Douglas fir and Grand fir, it is not possible to use source identified material from Irish seed stands, with source identified material available from the pacific North west. Perhaps this needs to be looked at again, especially in light of the potential for seed stands of western hemlockand Lawson cypress showing superior characteristics (e.g. Avondale and JFK park). Furthermore results from provenance trials/gene banks of these species in Ireland should inform suitable provenances of minor species.
With respect to the current accepted tree species for grant aid a number of suggestions are worth mentioning. For conifer species, the loss of Japanese larch which has been withdrawn from use in the afforestation scheme due to Phythopthora ramorum, it would seem logical at this stage to find a replacement. This could be utilised in mixture with Sitka spruce particularly for GPC3, to broaden the species palate.Other species might serve silvicultural functions at a local level and serveto increase the resilience of the forest estate, in the event of other species being withdrawn from approval.
The potential of minor conifer species
As part of a new study looking at the use of additional conifer species for use in Irish Forestry, Teagasc has compiled a list of 200 conifer species, some 130 of these have some representation in Irish Forestry having been planted in Arboretums or in trial plots. Further information on this study can be made available on request to the author. However the range of species with commercial potential is more limited. We have judged that it may be worth considering the following species that show immediate potential in Irish Forestry, includinggiant redwood (Sequoiadendrongiganteum), Pacific silver fir (Abiesamablis), European silver fir (Abies alba), noble fir (Abies procera), Japanese redwood (Cryptomeria japonica), Macedonian pine (Pinus peuce) and cedar of Lebanon (Cedrus libani). Many of these speciesoffer potential in mixed plantations and/or for extending the ecological range of Sitka spruce. They also deliver different functions in forest plantations such as shade tolerancewhich can be advantageous in mixed uneven aged forest plantations or in continuous cover forestry.
Noble fir (Abiesprocera)
Its natural range is the Pacific coast of North West America. Here it grows under a cool and moist climate where rainfall exceeds 1000mm per annum. This species is noted for its tolerance to exposure and is the most resistant to frost when compared to alternative fir species. It is most suitable at higher elevations on moist sites and can cope with poor nutrient regimes. It can suffer from drought crack so site selection is important. It is moderately shade tolerant and produces wood that is light but also strong (0.39 kg m-3). This species is widely free of any damage from pests or diseases. A provenance trial of noble fir is available in JFK park, Co. Wexford.
European silver fir (Abiesalba)
Its natural range is the mountains in central and southern Europe. It is also suited to a climate that is cool and moist with rainfall also exceeding 1000mm per annum. Like noble fir it’s most suited to upland areas but is more susceptible to frost damage and exposure than noble fir and therefore must be sheltered to an extent. It is a shade tolerant species that can also suffer drought damage. It can grow on sites where nutrients levels are poor but can’t grow on peats or soils that tend to dry out. It can be damaged by a number of pathogens with Heterobasidion being the most common. The timber is moderately strong for its weight (0.38kg m-3). A provenance trial of silver fir is available in Avondale, Co. Wicklow.
Pacific silver fir (Abiesamabilis)
Its natural range is from coastal Pacific North West of America. Rainfall in its natural range exceeds 1250mm per annum with a climate that is also cool. This species is cold hardy but can be susceptible to damage from late spring frost and also exposure and drought. It is a shade tolerant species which has slow initial growth but can perform as well as western hemlock or Sitka spruce. It can grow on soils that are poor to rich while also being relatively moist. It can’t tolerate peaty soils or soils liable to drought. This species is extremely susceptible to Heterobasidion. The timber quality is moderate to poor (0.36kg m-3).
Japanese Red cedar (Cryptomeriajaponica)
Its natural range is the central and southern island of Japan. Here the climate is categorised as being a warm maritime climate with rainfall above 1200mm per annum. The need for warmer growing condition may limit this species to the east and southeast of Ireland. It grows best on soils of rich to poor nutrient regime being slightly dry to moist. This is a very shade tolerant species which is moderately resistant to exposure but is affected by late spring frost but it can handle periods of drought. This species is mainly affected by Phytophthora root disease and also Armillaria root rot. This species produces a high quality timber (0.50kg m-3).
Giant Redwood (Sequoiadendrongiganteum)
Its natural range is from an area in the Sierra Nevada Mountains in California, America. The climate here is normally humid with relatively dry summers. It is noted for being more tolerant to exposure, drought and to cold than coast redwood (Sequoiasempervirens). It grows best on soil of poor to medium soil nutrient and of dry to fresh moisture regime. It won’t tolerate peaty soils or heavy gleys. It is a shade intolerant species that produces relatively fast early growth with the potential of producing high volumes. Like Japanese red cedar, it is susceptible to Phytophthora root disease and also Armillaria root rot. The wood is of poor quality (0.30kg m-3) but is very durable and suitable for exterior applications.
Table 1:Some conifer species worth considering for use in Irish Forestry
Conifer Species / Botanic name / CommentsGiant Redwood / Sequoiadendron giganteum / Climate change resilience, impressive production
Pacific Silver fir / Abies amablis / Good timber properties, quality appears impressive
European silver fir / Abies alba / Useage in Continuous cover forestry, must be in mixture to alleviate aphids risk
Noble fir / Abies procera / Useage with Sitka spruce in mixture, on high altitude sites, tolerant to exposure.
Japanese redwood / Cryptomeria japonica / Fertile sites, desirable form, similar to western red cedar
Macedonian pine / Pinus peuce / More tolerant to Dothistroma needle blight than other Pinus spp. and shows acceptable levels of performance on difficult sites
Cedar of Lebanon / Cedrus libani / Very high timber density offers potential for high quality timber products
The Birch and Alder programme
Teagasc has for a number of years being conducting research into birch and alder improvement conducted at our KinsealyResearch Centre. Recently the use of birch and alder has increased in the planting programme and seed is being produced from the Teagasc tree improvement programme is now being utilised in commercial nursery production. It is vital that this breeding work is maintained with linkages to industry to ensure the availability of high quality seed to the sector.
Birch (Betula spp.)
It is a positive development to see that birch ‘qualified’ is now eligible for planting as a commercial timber crop species and can be claimed as “GPC 8” for grant and premium purposes.
Alder (Alnus glutinosa)
Currently alder is grant aided and all categories within FRM i.e. from source identified to tested are acceptable. As part of the Birch and Alder Improvement Programme in Teagasc, one of the main objectives is to provide improved alder planting stock to the forestry sector. The programme is at a stage where clones of Irish plus tree selections are available to establish a commercial outdoor seed orchard with category ‘selected’ within FRM. It is hoped that as seed from this source becomes available in sufficient quantities, to supply the demand, that only the improved quality Irish material will be considered.
Other broadleaved species with potential - Hornbeam (Carpinusbetulus)
One broadleaved tree that is not on the list in the draft document is hornbeam (Carpinus betulus). Hornbeam is frequently confused with beech but is quite different in many respects. Similar to beech the leaves can remain on young hornbeam trees throughout the winter months. Hornbeam will grow in soils where beech will struggle or even fail such as heavy wet soils. Apart from being very frost hardy it can adapt to a very wide range of soils from wet heavy clays to very light sandy soils. It will thrive on both acid brown earths and soils derived from limestone. It will grow in full sun or partial shade and is an excellent tree for coppicing. Hornbeam has an excellent calorific value as well as being an important species for making charcoal. It can also boast to have the hardest wood of any tree in Europe. Unfortunately hornbeam does not have good form but by including hornbeam in the species list it would highlight the need for an improvement programme for the species.
Being very shade tolerant, hornbeam and beech are used extensively on the continent in mixture with other broadleaves as a silvicultural tool to help control branching and prevent epicormics. This si something that we in Ireland should be considering using in our young broadleaf plantations.
The numbered poplar clones in the consultation document were experimental clones and may not have gone on to be bred commercially. Clone 76004/10 became commercially produced and named as Grimminge.
The choice of best Sitka spruce provenances
On the use of Accepted Seed Origins/Provenances of Sitka spruce, much historical work is available on the subject and current provenance recommendations are based on the results of extensive IUFRO provenance trials of Sitka spruce based on unimproved seed (Pfeiffer 1982, Thompson et al. 2005). However relatively little formal experimental testing of improvedmaterial from various breeding programmes has been carried out in performance comparison trials. To address the issue, Teagasc established a series of provenance experiments covering 5 different provenances located at Athenry, Ballyhaise, Oakpark and Johnstown castle. The trials involved five provenances current available to the Irish planting programme notably;
- Improved QCI material (Forestry Commission TIP[1])
- Unimproved Washington material (Seed Stand Material)
- Improved Washington material (Denmark seed Orchard)
- Improved Washington material (Veg Prop Coillte TIP)
- Unimproved Oregon material (Ocean Lake)
While the trials are in their 3rd year, it is worth considering some initial results of survival, damage, height increment and total height growth to observe if differences between provenances are apparent.
Survival of provenances
The effect of provenance on survival was significant ((P<0.05) at Athenry, Ballyhaise and Johnstown castle. At Athenry and Ballyhaise, theImproved QCI material showed increased levels of survival compared to the Improved Washington (Veg Prop Coillte TIP) material. Survival in the improved QCI material and unimproved Washington (Seed Stand)material was over 98% at Johnstown castle with showing significantly lower levels of survival compared to the unimproved Oregon (Ocean Lake) material (92%) (p<0.05).
Table 2: Survival of provenances at Athenry Sitka spruce provenance trial (different letter indicate significant differences).
Provenance / % / DifferenceQCI Improved (UK) / 100.0 / A
Washington Improved (DK) / 97.2 / B / A
Oregon (Ocean Lake) / 97.2 / B / A
Washington Improved VP (IE) / 90.9 / B
Damage to tree leaders
The effect of provenance on leader damagewas significant at Athenry, Ballyhaise and Johnstown castle. Significantly greater damage to leaders was apparent on the Improved Washington (Veg Prop Coillte TIP) sources compared to all other provenances at Athenry (P<0.05). While damage to trees was observed on all provenances in Ballyhaise, it was highest in Oregon and the Improved Washington (Denmark seed Orchard) material at 30% of stems showing leader damage. The unimproved Oregon showed significantly higher levels of damage compared to improved QCI and Improved Washington (Veg Prop Coillte TIP) material. Similar results were apparent at Johnstown castle with Oregon showing higher levels of damage compared to other provenances.
Table 3: Damage to provenances at Ballyhaise Sitka spruce provenance trial (different letter indicate significant differences).
Provenance / % / DifferenceOregon (Ocean Lake) / 33.3333 / A
Washington Improved (DK) / 30.1167 / B / A
Washington standard (IE) / 17.6000 / B / A / C
QCI Improved (UK) / 14.8167 / B / C
Washington Improved VP (IE) / 11.1333 / C
Height Increment after 2 growing seasons
No apparent difference in height increment for different provenances was detected at Athenryor Ballyhaise where the effect of provenance on height increment was not significant.At Oakpark theImproved Washington (Veg Prop Coillte TIP)showed lower levels of height increment compared to all other provenances (Figure 1). Similar results were apparent at Johnstown castle where the Improved Washington (Veg Prop Coillte TIP) showed significant lower height increment growth compared to other provenances. The Improved Washington (Denmark seed Orchard) only showed increased growth compared to unimproved Washington (Seed Stand Material) and Improved QCI material at Johnstown Castle only after 2 growing seasons.