Farm Forestry New ZealandIndigenous species - Silver beech, Nothofagus menziesii, Lophozonia menziesii
Species guide
Silver beech is a native hardwood that is found in cool forests from the Bay of Plenty to the bottom of Southland. It is a relatively slow growing tree, reaching up to 30 m high and up to 2 m in diameter. It lives for 500-600 years, tolerates cold and will grow to altitudes of 1200 m.
Commercial return: Low
Site requirements
Altitude
Moderate altitude; Low altitude;Rainfall
High rainfall;Soil depth
Deep; Moderate depth;Soil drainage
Free draining; Moderately free draining;Temperature
Cold;Wind
Moderate wind;Site preparation and planting
Silver beech regenerates prolifically in natural forests and establishes well from seed. The species has a modest growth rate.
Silver beech seedlings are shade tolerant but while young are susceptible to drought and frost, and establish best if planted in partial shelter such as within canopy gaps.
Prepare grass sites by spot spraying a one metre circle for each planting site. Use glyphosate herbicide with spray dye a few days before planting as this will not leave chemical residue in the soil. Prepare spots using straight lines and accurate spacings between spots so that trees can be easily found later. Cut down woody weeds and flatten these on the ground so they decay and don't support weed growth.
Planting
Trees are generally available from commercial nurseries as container grown stock. Price per tree should range from $2.50 - $5.00 for 1-2 year-old contract-grown forestry stock (2020 prices).
Plant as soon as possible after you receive the plants. Make sure the root plugs are moist and plant trees with a slow release fertilizer tablet or put a trowel of high nitrogen fertiliser such as DAP or urea in a spade slit above the seedling.
Dig a hole twice the size of the plant container, leaving some soft soil at the bottom. Tease out (straighten and trim) any pot-bound roots before firming the soil around them, ensuring there are no air cavities.
On colder sites plant in early spring; in warmer areas with no hard frosts, plant from autumn.
Silver beech will establish in open sites, but will have better form (taller and less bushy) and improved timber properties (fewer, smaller knots) if some side shelter is provided. A nurse species that grows fast initially but does not grow too big (e.g. manuka) can be planted to provide side shelter. The nurse crop should ideally be planted a few years before so that shelter is well established before planting the beech.
Spacing
On disturbed forest sites silver beech seedlings can come up prolifically, but a reasonable spacing for planting beech in a canopy gap or an open site is 2–3 metres apart.
Spacing for planting beech in an open site is 2 x 2.5 m (2000 stems per hectare). The higher the number of trees planted, the greater the selection ratio for retaining only the biggest, straightest crop trees.
If using a nurse crop, plant the nurse species at 2 x 4 m apart, then inter-plant with beech later at 2 x 4 m spacings.
See Site preparation and planting
Establishment and Maintenance
Remember:
- Prevent weeds from competing with the Silver beech seedlings for at least three years after planting.
- Protect seedlings from browsing by stock and wild animals.
Releasing
Ensure the newly planted tree gets enough light, moisture and nutrients to establish unimpeded. Maintain young trees by clearing or spraying weeds around them for at least two years or until they are well established and growing. Seek advice on choice of chemical if release spraying.
Native trees, being slower growing than exotics, may require releasing from weeds for several years so they don't become smothered by early weed competition.
During establishment Silver beech responds to side shade by growing faster, straighter and taller with fewer branches. A nurse species that grows fast initially but does not grow too big, such as manuka, can be planted to provide side shelter. The nurse crop should ideally be planted a year or two ahead of the Silver beech.
Overhead shade slows down growth. For good growth rates release trees from competing vegetation so some direct sunlight always reaches the tree’s leader. Climbing plants and dense woody weeds can overtop young native trees and may require manually cutting back to provide a light-well for the young tree to grow up through.
Where Silver beech regenerates with manuka and gorse it will overtop these species within two or three decades, sooner if provided sufficient light.
See Successful establishment of tree seedlings »
Grazing/Browsing
Beech is susceptible to browsing by stock, goats and deer so fence the area to keep them out. A single hotwire electric fence will deter most cattle, but it is best to construct a full post and wire fence.
Beech is not a preferred food of possums but is palatable to rabbits and hares. They will slice off trees near ground level at a 45 degree angle, killing them.
Pests and diseases
A native pinhole borer attacks stressed or damaged silver beech trees and moist harvested logs, drilling pinholes in the wood. Healthy trees will survive an attack but the pinholes can allow a fungal pathogen into the sapwood, which can damage the timber and sometimes kill the tree. In the North Island trees can also be attacked by the larvae of the puriri moth, which bore relatively large holes and also let in fungal pathogens. The kanuka long-horned beetle attacks saplings in both islands.
Many native leaf-eating insects feed on beech canopies. The trees have evolved sufficient hardiness to survive most of these attacks.
See Forest establishment and maintenance
Management and silviculture
Silver beech is the slowest growing of the beeches. Silver beech does not generate honeydew.
Suitability for steep slopes: Natural beech forests provide watershed protection. Although they tend to have shallow root plates the roots of closely spaced trees will interlock, making them wind-stable and suitable for exposed, eroding hill country. Silver beech does not coppice: the stump dies when the tree is felled. See Report: Trees for steep slopes - Beech, Southern »
Pruning
Form pruning: If grown for timber, form prune at regular intervals to encourage a single dominant leader, and prune the trees every two years to prevent lower branches from getting too big. Pruning can begin once the trees are well-established and above the height of any competing weed vegetation – e.g. from around 2 metres tall.
Form pruning guidelines are available here.
Clearwood pruning: The aim of clearwood pruning is to minimise the defect core and produce wood free of knots. Pruning "lifts" must be regular and undertaken at a frequency that minimises branch size and diameter over stubs (DOS). Ideally, only final crop trees would be clear-pruned. The smaller more horizontal branches on lower stems of Silver beech established within a highly-stocked stand (i.e. 1600 stems per hectare or more) will generally self-prune when they are shaded out. Larger, upward pointing branches should be removed as soon as possible as they will reduce height growth and increase defect core diameter.
Clearwood pruning guidelines are available here.
Pruning should be completed a year or two before thinning to reduce the likelihood of "epicormics" (shoots forming on the pruned stem). Pruning often attracts deer wanting to rub velvet from their antlers, resulting in ringbarking of the trees. Deer control is necessary to prevent this from occurring.
Suitable pruning tools include loppers and a pruning hand-saw, a battery-operated reciprocating saw, or battery-operated loppers. Form pruning can be undertaken by using a pole pruner.
Thinning
Close spacings provide better height growth and small branches but with a reduced diameter growth rate. Thinning is required to reduce stocking (number of trees per hectare) and encourage diameter growth in residual "crop" trees.
Close spacings provide better height growth and small branches but with a reduced diameter growth rate. Silver beech trees are shade tolerant, so are slow to self thin and densely-planted stands will remain as poles, with good form but too small for milling. When thinned, they produce faster diameter growth and the residual crop trees grow larger.
Thin once the canopy has closed and before the trees get too tall, e.g. at 8–9 m in height. Stocking should initially be reduced to around 1100 – 800 stems per hectare (around 3–4 m apart) by removing poorer quality trees. Thin again once the canopy closes a second time, e.g. around 6 years later, to a stocking density of around 500 – 600 sph (approximately 4–5 m apart). The trees could be left at this stocking, or later given a third thin to as low as 200 sph (7 m apart)
When to harvest
A survey of beech plantations on a range of sites shows that mean diameters of 50 – 60 cm can be achieved within 100 years of planting. A minimum 70 year rotation is suggested for silver beech and a continuous cover regime is recommended.
See Silviculture and forest management
Timber utilisation
Silver beech is a medium density hardwood with fine, straight grained and even textured wood, sometimes with handsome figuring. It makes clean veneers; it is relatively easy to dry; when dry it is strong and stable and steam bends easily. Neither the heartwood nor the sapwood is ground durable but it is resistant to borer, attractive and well suited to indoor applications such as joinery, furniture and flooring.
Markets and demand
South Island sawmills trade silver beech.
Harvesting of Silver beech is controlled by the Forests Act (and must be undertaken sustainably). Planted Silver beech may be harvested for timber without controls if the owner has obtained a certificate from the Ministry for Primary Industries. The process is described here.
More on silver beech timber »
Growth, yield, economics and carbon
Annual growth rates of planted silver beech usually range from 20 to 25 cm in height and less than 1 cm in diameter, although it can grow faster on fertile sites. A survey of stands gave average heights of 13 metres 40 years after planting and 17 m at age 60. Samples measured 32 cm diameter at breast height (DBH) at age 40 and 45 cm DBH at age 60.
This paper offers some advice on monitoring growth.
Timber return on investment
No published calculations show return on investment for growing Silver beech for commercial purposes. Although a simple calculation suggests earnings from carbon credits might overtake the costs of establishment after 20 years, this calculation is sensitive to every assumption and no claim is made that it is true or accurate. The assumptions used were:
- Establishing 400 stems per ha at $5 per stem ($2,000 per ha)
- Cost of capital 5% pa real
- Lookup tables for indigenous forests apply: price of carbon $30 per NZU real
- Excluding the costs of land, rates, management and ETS compliance.
Carbon sequestration rate over time, and relevant Look-up Tables
If the land is registered under the Emissions Trading Scheme and the trees are planted so as to comply, i.e. at least one hectare, with tree crown cover of more than 30 percent in each hectare and an average width of tree crown cover of at least 30 metres, then they should earn carbon credits. The relevant look-up tables for determining how quickly they store carbon and earn credits, and guides to how to use the tables, may be downloaded here.
As Silver beech is an indigenous hardwood, tables A2.2 and A2.4 apply, suggesting that over its first 30 years Silver beech stores carbon at a rate of approximately one third as fast as radiata pine.
Outside the ETS this carbon calculator suggests how much carbon a planted native forest will store over time.
Further reading
- The New Zealand beeches: establishment, growth and management, NZ Indigenous Tree Bulletin No. 6
Smale, S., Bergin, D., & Steward, G. (2012). New Zealand Indigenous Tree Bulletin No. 6 (pp. 64). Rotorua: NZ Forest Research Institute.
Full colour handbook covering all NZ’s beech species. Includes management of natural stands and some information on establishing new plantations. Best available information on all aspects of growing and utilising the beech species. - The Seasoning of New Zealand Beech Species
Utilisation Development Division Report No. 14, R.K. Bagnall (1971). - The Air Drying of Beech in Westland and Nelson
Utilisation Development Division Report No. 9, NC Clifton (1968). - Expanding economic viability for sustainably managed indigenous beech forests
Donnelly, R. H. (2011). Expanding Economic Viability for Sustainably Managed Indigenous Beech Forests. Christchurch: NZ School of Forestry.
Comprehensive report focusing on markets and the market potential for indigenous beech. SFF project 05/048, co-funded by University of Canterbury, NZFFA, Maori Trustee.
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