Acotanc: Greening Australias Involvement in Low Rainfall Farm Forestry

Greening Australia's Involvement in Low Rainfall Farm Forestry

Author: Tim Emmott
author title
E-mail: [email protected]
Organization: Greening Australia
Avon Catchment Network
PO Box 311, Northam, WA, 6401
Phone: +61 8-96902257 Fax: +61 8-96902255
E-mail: [email protected]

Greening Australia is working to encourage the planting of trees on farms in low rainfall areas in the wheatbelt. In order to get the most benefit, high value specialty timber trees are emphasised. Various species are discussed.

Everyone knows that trees are needed back in the landscape. Try to plan and make sure you get as many benefits as you can, one of them, hopefully, being commercial. So, Farm Forestry is really commercially-driven landcare, or environmental benefits plus tree products. It is known that revegetation can combat salinity. There are substantial up-front costs associated with establishing trees. With revegetation, you try to look to generate a future income stream.

Some of the benefits I am sure you are all aware of are controlling groundwater recharge, shade and shelter for livestock, which is really overlooked. Animals perform a lot better if they are not stressed by the elements. Soil stability, protecting crops and pastures from harsh winds, and providing cover on unproductive land. Improved aesthetics and biodiversity. You only have to speak to a certain number of real estate salesmen to find out that they find it easier to sell properties that have trees planted the edges of the paddocks, for higher prices. Providing a future income stream, and farm diversification.

One thing that is really important is to plan your project so you get as many benefits from your plantings as possible. Determine your goals and objectives. What you are trying to do with your tree planting project. If water use is your main thing, or you want a windbreak. It is really important to work out in your own mind what it is that you are trying to do to help in your species selection.

Identifying the suitability and potential of your site is very important. Determining the end-product to be produced, having it clear in your own mind what product you are trying to produce before you start. This will let you know what management requirements are going to be, and the availability of labour to meet those management requirements. Another thing to consider is access to the site for future harvesting.

I will focus on specialty timbers today. Some of the options are oil mallees, heaps of potential there; Sandalwood; fodder shrubs; timber production; native foods; seed production; and cut flowers and foliage. There has been a lot of work done on Sandalwood. CALM or Forest Products have got share farm agreements. You are ahead from the start when you grow Sandalwood, as it is a WA native. It is adapted to the harsh conditions of the WA environment. It is a very high-value product with an established market. Sandalwood in WA has been exploited for more than 100 years. It is relatively slow growing, susceptible to fire and grazing, but once established, there is minimal management. That could be more attractive to some people than some of the other options that require on-going management.

It requires a host species: Jam (Acacia acuminata) is the most common one used in plantations, but sheoak and many other acacias will also do the job. It prefers well-drained loams but will grow on gravels and yellow sands. Fencing is a definite requirement if you are running sheep, also for roos and rabbits. The preferred method is to establish the host species first, and then direct-seed Sandalwood when the hosts are about 2 m high, placing 4 nuts per tree, within half a metre of the host plant. Use fresh seed from local provenance. There are provenance trials going on. Weed control is very important during the early years.

We will just talk about trees for timber. It is quite well known that there is a diminishing supply of wood from native forests around the world. This has been caused by many factors: forests being cleared for agriculture in developing countries. Southeast Asian countries are still opening up vast areas of land to agriculture. Once that resource is logged, it is sold and not replaced. The condition of forests world-wide is declining. Forests have been placed in reserves that exclude logging. The development of carbon credits is making timber production a bit more attractive. Products from trees and shrubs are a renewable resource. With the way the world is thinking, there is a lot more push towards using sustainable products. Iron, once it is mined is irreplaceable, but can be recycled. Timber can be sustainably and renewably produced products, a good plus for timber production.

Projections for global demand for wood in 2020: demand and supply--there is a big gap there that wheatbelt landowners might be able to help fill by producing timber on their farm for conservation benefit.

Sawlogs can be mixed in with the specialty timbers. Some of the options for low rainfall areas are Sugar Gum, E. cladocalyx,River Gum, E. camaldulensis. There are a few considerations with E. camaldulensis that I will touch on a bit later. Wandoo, Brown Mallet, Flat Top Yate (a bit of salt tolerance), Spotted Gum, Lemon-Scented Gum (not suited to below 350-400 mm rainfall areas), Red Ironbark and Maritime Pine. Just some of the options. Some of the specialty timbers that can be grown on farms for high-value timber products include Salmon Gum, Gimlet, Red Morrel, York Gum, Rock Sheoak, Mulga, Western Myall. Some of the Cypress Pines are getting a look-in now. And the River Oak, Casuarina cunninghamii. Firewood is another potential--there are plenty that produce great firewood.

With all the specialty timber species, the source of the seed is very important. Where you get your seed from, and the nursery that supplies your seedlings. Use a reputable nursery and make good contacts. Make sure they can supply seed from good provenances, with known performing provenances of trees and good quality seedling stock.

Anyone who is going to be growing specialty timbers has to be aware that there is going to be management requirements if you are going to produce a quality product. Good establishment is essential, weed control, ripping, mounding, all of that. You will have to do some pruning over the life of the project to produce knot-free timber, or clear wood. You might also have to do some form pruning. Thinning will be required, like culling sheep. You will have to remove unwanted trees to reduce competition, aiming to keep the best, healthy trees, vigourous, straight trees so you get some good clear wood growth. Down to the final stocking density of not more than a hundred trees per hectare in the low rainfall areas.

This is an example of thinning in a well-known timber plantation. Taking out some trees, to reduce competition to allow these trees that have been pruned at six metres to grow in diameter. If you are producing timber, you try to produce a log of about 50 cm approximately 6 m in length. It has to be straight.

There are many different designs that landowners can use for farm forestry projects. Just the importance of silvicultural pruning: this is an example of E. grandis, six years old. This just shows you the difference that pruning can make--these are exactly the same trees, growing in exactly the same conditions. Pruning the trees will give you that valuable product, but if you leave them unmanaged, you really will have trouble getting a salable product.

Clearwood pruning is usually done when the trees are about 9 or 10 cm in diameter and about 4 m high. The lower two-thirds of the tree is pruned, leaving a good developed crown.

Everyone here will know of Wandoo and how tough a timber it is. It has been used extensively since European development. Aborigines had a lot of uses for it, as well. It is a preferred construction timber, one of the best railway sleepers known. Nowadays it is used for quality flooring and furniture. It is a beautiful colour and very strong. It is extremely durable and white ant resistant. However, growth rates are not rapid. You wouldn't expect to have final harvest in less than 30 years, I think. But Farm Forestry is about growing these trees to get a lot of other benefits along the way. On-farm benefits. Wandoo is known to be a high water user. There is an established market for Wandoo, limited by supply. Most of the Wandoo comes from native stands, many of which have been placed in reserves that exclude logging.

This is a Mount Bedly (?) farmer with a Wandoo plantation. Would you like to have a guess how old this is? It is nine years old. It is not great growth. Anyone who has had anything to do farm plantings of eucalypts in medium to high rainfall zones would know that this is not exceptional growth for nine years. But this growth is in 450 mm rainfall area, an unproductive site that he couldn't crop. So now he has a really good future resource coming on. It was grown by his grandfather to produce strainer posts, but now he is managing it, hoping to grow quality furniture. One problem with that site is that it is at the back of the farm. If he is going to get a contractor to come in, they will have to cross over two or three creek lines. That is one thing to consider: where you put your plantation, you will have to get big logs out, and big machinery in to harvest.

Brown Mallet is another species that has been used extensively. There are established industries down in Narrogin. A well-developed but limited market. The wood machines well for craft wood. It is a shock-resistant timber used for specialty tool handles, mallet handles and that sort of thing. It is adapted to most well-drained sites, with a medium growth rate.

Flat Top Yate. This is not a good example of a timber tree. Flat Top Yate is being trialed a lot in many situations for potential sawn timber. It does have some salt tolerance, but I wouldn't recommend trying to grow timber trees in salty areas. They will be struggling so much from waterlogged and saline conditions, I think you are better off to try to grow timber trees higher in the landscape where they have access to water a bit fresher and stop a bit of water reaching the lower areas. There is a high tannin content in the bark.

Sugar Gum is one that is really great in low rainfall areas. It is the main source of firewood for Adelaide, grown on farms. It is adaptable to many soils, including deep sands. It is a South Australian species. The supply of seed is very important. I have some brochures for anyone who is interested. The CSIRO Tree Seed Centre in NSW or Canberra can supply good seed from known, performing provenances.

Eucalyptus camaldulensis has many different and varying provenances. Some of you involved in revegetation would know. Silverton, Lake Albacacha (?), there are many, even one in the north of WA. It is being exploited on the Murray River. It is a hard, durable, deep-red colour, but is a bit difficult to saw and to dry. It is very adaptable to many soils. Some types have some salt tolerance, but is very susceptible to parrot damage. One of the biggest risks for timber production is Twenty-Eight Parrots. They nip and attack the tops of the trees, causing forking and causing the top to die. It is a really big risk you have to consider before establishing or going into timber production on a large scale. In low rainfall areas, tree planting is done on a very large scale, and you want to keep your capital costs as minimal as possible. In a lot of situations economic gain or commercial gain is a secondary thing. The trees are mainly planted for landcare reasons. To spend up-front costs of netting to protect the trees would just put it out of perspective. The only methods of parrot control I know of have been trapping and shooting, and also disturbing them at night where they are nesting, so they move on.

E. sideroxylon, Red Ironbark, is another one grown in low rainfall areas. A lot of foresters from CALM are now saying to replace this with E. tricarpa, which is another form of Red Ironbark. Very tough, durable timber, excellent applications for electric fence droppers, good insulation properties. Medium growth rate, suited to some pretty crappy soils, shallow soils, gravels. It has been used for railway sleepers. Native to Victoria and NSW. It is a very attractive tree, if you want to improve the aesthetics of your farm.

Lemon-Scented Gum and Spotted Gum. As I said before, just be careful when coming down to low rainfall areas. They are grown extensively in the medium to high rainfall areas. They are susceptible to frosts. Spotted Gum is a very shock-resistant timber, good flooring and furniture production, suited to sandy loams and gravels, preferring moisture-gaining sites. Parrot damage, again, is a bit of a problem.

I am still learning about specialty timbers, but I will pass on a few things. Generally, they are slow-growing, but when you say 'slow-growing,' that is comparing with timber production in high rainfall areas. They still do grow quite well in the wheatbelt. It is the potential to achieve high prices by value-adding, looking for specialty craft things or wood turners, or that sort of thing. Many species native to the wheatbelt are suitable and have a record of performing well in general revegetation. Things like Salmon Gum and Gimlet, Red Morrel, have been used in many revegetation programs. That is a good indicator for anyone who has been doing revegetation--just to see what has been performing well, and knowing how to manage them and grow them so they produce a quality product. There might be niche markets for the thinnings, so the timber you are taking out might be able to be sold for wood turning. Many of these species offer unlimited cultivation benefits, being native to the area. People are growing them. This is a farmer in between Wongan Hills and Goomaling, Salmon Gum growing natively. He has collected seed from the local provenance from the straight and taller trees. This area was contributing to rising water tables, erosion, it was cracky, a bit rocky. So he has established specialty timber there. We just had a field day there, just having a look, not ready for management yet. It has had some parrot damage, but they are going to do some trapping. There is some Red Morrel there, Sugar Gum and Spotted Gum as well. People are growing these trees for timber production.

This is a Salmon Gum plantation in South Australia, well-suited to the rainfall types out in the low rainfall areas. It is a strong, durable timber, a beautiful deep-red colour. I reckon it is a great substitute for Jarrah, in terms of how it looks. It is a pretty hard timber, but it can be sawed quite well. The timber can sell for up to $3000 per cubic metre, sawn and dried. It is known to be a slow-growing tree, a very attractive tree. Again, try to get as many benefits along the way when you grow these trees. It is quite shallow-rooted, and farmers in the wheatbelt know they do fall over, after summer rains and strong winds. This is a wind-fallen tree that was slabbed up, and the slabs sold for $180 each, six slabs off the tree. It is quite a sought-after timber.

Gimlet is well-known for its applications for musical instrument manufacture. It is known to be slow-growing, but don't let that put you off. If you think, 'I'm not going to grow these timber trees because I will never see the benefit,' I think if you sell your farm and you have a well-managed timber plantation on your place, especially timber that is going to increase the value...if you pass it on to your kids, they will get the value. You benefit anyway, even if they are long-term projects. For more information on these, CALM Timber Technology in Harvey have information.

Rock Sheoak, Allocasuarina, very attractive timber with a unique, distinctive grain. There is an existing market, but is limited by supply. All of the people I have spoken to can't get enough of it. It is associated with granite outcrops and the deep granite sands of the wheatbelt. It is a known Sandalwood host, so Sandalwood can be grown off it. They are nitrogen-fixing. There is not a lot of work done on provenance selection. That is where you need to work with your local seed-collecting company or seedling supplier.

Beefwood. There is not a lot of record of this being grown extensively for revegetation, but at the moment it is one of the most expensive specialty timbers harvested in WA. It is native to the northern Goldfields. It is called 'Beefwood' because when it is cut it looks like a freshly-cut piece of steak. It is really attractive timber. Drought and frost tolerant, so it is a pretty tough tree, but it is sensitive to extensive wet and cold periods. There are a few farmers putting in a few hundred of these this year out in the wheatbelt, just to try them out. It is a bit of an experiment to see how they go.

Dundas Mahogany is another timber tree that can be grown. It has an extensive root system, very hard, durable timber. Native to the Corrigin area, medium growth rates.

Casurarina p....(?), the Black Oak, is another one that is becoming more recognised as a specialty timber. The Callitris species are getting a bit of interest nationally as low rainfall timber trees, but there are a lot of variances within Callitris. Some of the ones out by Hyden will only grow to 2 m tall. You have to be quite specific if you are getting seed for these. There can be a bit of trouble germinating these seeds. I heard of one person having to put them in a fridge for a month before growing them. They are very attractive Cypress Pines, have been exploited from many stands throughout southern Australia. It has been used to build boats in Adelaide. Young trees can be used as Christmas trees. But, very slow-growing, long-term.

Redwood, E. transcontinentalis, also native to the Goldfields, similar to Salmon Gum. This one hasn't been used commonly in revegetation projects in the wheatbelts. To find out about them, talk to people who have been growing them. Very drought tolerant.

Red Morrel is one that is really quite in demand, especially the burls, for making knife handles, specialty turning work. Again, a deep-red colour. It prefers heavier soils. Highly durable heartwood, high frost tolerance, very drought tolerant.

Western Myall and Mulga. Western Myall has a bit of trouble growing in the wheatbelt, but Mulga can be grown extensively, no worries. Mulga is used for fence posts, like Jam. Jam, Acacia acuminata, is beautiful timber, but a bit unstable for wood-turning, tends to crack a bit. Mulga is quite similar, has been used for specialty work. Frost tender and very palatable to grazing animals, but can tolerate some waterlogging, and also is a Sandalwood host, although probably not the most ideal Sandalwood host because they are quite slow-growing and the Sandalwood might outgrow it.

In growing these timbers, you try to get a 6 m stem, so you get two 3 m logs. You prune 6 m clear of branches, because where the branches are there will be a defect in the wood. When buying nursery trees, tell the nursery that you want to grow the trees for timber and ask if they can supply good straight trees. With some like Sugar Gum and River Red Gum, Maritime Pine, there has been work done on the provenances of them and you can get good seed that comes from known, performing provenances. With others, like Salmon Gum, the best option is to look around your own property and see where you have good, straight trees and collect seed from them. It is hard to collect seed from a tall, straight tree. You can shoot the branches down. A lot of nurseries in the wheatbelt, Wongan Hills, are really quite switched onto it now and are providing seed from good trees for these specialty timbers.

There is quite a lot of work being done with eucalyptus hybrids. Salmon Gum won't cross with E. grandis. They have crossed Blue Gum with the River Red Gum to try to get them into low rainfall areas, and there is more work going on with that, but probably commercial seed won't be available for a while. CALM are trialling casuarina hybrids, Casuarina cunninghamia crossed with Casuarina glauca, for specialty timber production in salty, wet areas. CALM and AgWA are good contacts for information.

We have some trial sites in Greening Australia located in Hyden, Narembeen, Calingiri, Jerramungup and Morawa. The northern WA E. camaldulensis is crossed with E. rudis, so Flooded Gum is crossed with River Gum. We don't have any data yet from the trials. The trial in Hyden is for waterlogged, sandy areas. We are trialling E. rudis, a cross of E. camaldulensis and E. rudis, and as a benchmark we are using the Silverton provenance of River Red Gum. We are trying to introduce another forestry or timber option for low rainfall areas. We did a milling trial, found quite a lot of borer attack defects. Our little project is quite small. CALM and CSIRO are doing a lot of tree trialling, also AgWA.

Cape Lilac is a very sought-after timber for wood turners, but Greening Australia tries to focus on native species. I don't know much about it.

Scalping is a process commonly used in broad-scale tree planting. The main benefit of scalping is that it can be done as a one-pass operation. Tree planting in the wheatbelt is done on a broad scale with a mechanical planter, no hand planting, over 10,000 per day. So if they can come in with these Chatfield tree planters that rip and scalp...scalp gives good weed control and also allows for a bit of water harvesting by leaving a bit of a furrow. Mounding is more beneficial in wet areas, in fact, most areas, except where the mound has a tendency to dry out from the wind. Mounding has generally proven to give the best establishment. We try to leave grass in between the rows of mounds, for the locusts--the locusts will preferentially go to the grass rather than the trees. They try to keep the mounds weed-free for the first couple of years. Ripping is important where there is hardpan from compaction. Weeds are knocked down with a residual.

You should document your tree planting in your farm plan, that it has gone in as a forestry project, with photographic evidence that you planted these trees, just to document it yourself, to make sure there is no confusion that it was remnant vegetation. Make aerial photos to show the bare bits at the beginning. You should have a harvesting plan before you go in to harvest your timber lot, the time of year you are going to do it, how you are going to go about it and that sort of thing.

I think the personal experience of growing trees is quite special. I have seen trees do so much good on a farm. That on its own is generally enough to provide value to most people.