Thursday, 9 April 2015

Trees rock!

If tomorrow someone said they'd invented a self-reproducing tool for atmospheric carbon sequestration, improving water catchments, oxygen production, air filtering, low-carbon building materials, stock shelter, riparian zone protection, erosion management, food, bioenergy, firewood, biodiversity, habitat, paper manufacture, salinity control and recreation they'd be the Bill Gates of the 21st century. We don't have to wait for this invention as trees already exist!

At PragSust we think trees rock. We're developing an agroforestry or farm forestry site on our farm in Sth Gippsland with trees planted for multiple outcomes including many of the above. Ten years ago there wasn't a tree on the place except for some aging, exotic, remnant shelterbelts, a few paddock acacias and a few acacias on steeper slopes where the cows hadn't grazed as intensely. The previous owners planted some trees and we're planting a load more. We're particularly interested in durable timbers, fat logs for slabs and boards, high-value fine timber, roundwood construction using coppiced trees, bee fodder and craftwood for woodturners, garden use and rustic furniture. And we want to continue grazing cattle on the block.

Families owning woods for multiple outcomes is common in some of  the Scandinavian nations, parts of the US and Canada and increasingly in the UK. And farm forestry has become very popular in New Zealand. The length of time required to grow trees to a harvestable size is considerably less in Australia than in many parts of the northern hemisphere. It's quite realistic (in higher rainfall areas) with the correct site, species, outcome and management to start seeing some returns after ten years or so. Although a 20-40 year planning window does open things up a lot.

Some local landowners are also interested in these smaller-scale applications. So we thought we'd put together an initial checklist of some points to consider as part of planning trees on land. While written mainly for landholders this can also be useful in an urban setting. We've planted trees in our garden for bees and food but we do use prunings for other purposes.

Here's the list. Let us know what you think.

i/ What are the site characteristics? Soil, rainfall and temperature across the year, aspect, prevailing winds, slopes and contours.

ii/ What are your objectives? Construction timber? High value timber? Posts? Poles? Food? Onfarm use? Selling off-farm? Firewood? Bioenergy? Wattle structures? Rustic furniture? Bee fodder? Stock shelter and shade? Erosion management? Biodiversity? Habitat?

iii/ Do you want to have a go at practices like coppicing and hedge laying?

iv/ Timeframe. How soon do you want a return? Will you leave the property - and trees - for your children?

v/ How much area do you want to use for trees? Will you plant fence to fence, scattered in a paddock or in small coupes/woodlots?

vi/ Do you want to plant exotics, natives or a mix?

vii/ Do you want a monoculture plantation - some species occur naturally in largely single species stands - or to employ analogue forestry or another mixed species approach?

viii/ Budget. Will you grow some seedlings yourself? It's cheaper to raise trees from seed but it does require time and some skills. Specialist tree nurseries are good at growing trees and will save you time and effort.

ix/ Will you prune yourself? This will involve ladder work. Watching NZ videos of people pruning 12m high is sobering. Pruning for 6m clearwood logs is a common aim.

x/ How will you exclude stock and manage opportunistic browsers such as deer, wallabies and rabbits ?

xi/ Weed and fire fuel load management plan. Once stock are excluded grass and weeds will grow. Once the canopy closes in a densely planted coupe, grass and weeds will be suppressed but that will be some time down the track and may not occur for some weeds, such as blackberries, depending on the type of planting. Blackberries are a tough, successful plant that wants to grow in woodlands and forest edges. As well as rank grass and weeds, once the trees start dropping bark, dead branches, windthrow etc this is potentially a fire risk.

xii/ Will you harvest and thin yourself? This raises issues about safety and training in felling and chainsaw use. Forestry is about the most dangerous rural activity.

xiii/ Will you want to clear-fell - again well-suited to some species natural response to events like fire and cyclone - or use a technique like continuous cover forestry?

xiv/ How much time do you want to spend on forestry per annum?

xv/ What tools will you use? What do you own, what will you buy or hire and what will you get contractors to do? This will depend on whether you want to fell, buck and limb yourself or contract a harvester, use farm equipment to move logs or contractor trucks on farm tracks/roads (which will need to be a suitable standard for trucks to use), mill onsite or at a sawmill (which will require transport to the mill) and so on. Harvest is easier for  the farmer when done by external parties but there is less return to the grower. And for some sites it is prohibitively expensive to get contractor equipment to the coupe so the only option is smaller scale harvesting

Black cockatoos tucking into pine cones in a shelterbelt.

Cows in shelter on a warm summer day. These trees are under ten years old.

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