Future Proofing Your Land – Trees

When we talk about future proofing your land and trees most people’s thoughts will jump to firewood trees and shelter belts. But trees have many more purposes in the landscape. In the wake of such a volatile weather year for much of New Zealand this is an important subject for us all to consider.

Trees have an amazing capacity for absorbing and holding water, and this can be of great benefit during high rainfall events. A 5 year study lead by Scion Research, has shown that over the 2023 Auckland Anniversary weekend floods and Cyclone Gabrielle, 60% of the rain fall in the Mahurangi forest area (indigenous forest) was captured and stored in the forest’s catchment. It also noted that the soil near the surface did not saturate. This greatly reduced the erosion risk in that area and the amount of water and sediment which entered the surrounding waterways.

We have observed the increased water flow across our landscape post pine harvest of both ours and our neighbours plantations. While we are definitely not fans of mono crop pine plantations (see the The Argument Against Pines at the end of this article) it does offer an excellent example for how trees improve the water holding capacity on the land. It is our aim to regrow this capacity with trees that are more suited to our landscape and multipurpose.

Introducing mixed plantings of trees and shrubs across your property can greatly improve the lands resilience to extreme weather such as drought or heavy rainfall. Careful thought of how and where to do this can develop plantings which are functional for other reasons too. Riparian plantings are the obvious go to planting solution, but the use of traditional multipurpose hedgerows or wider planting corridors should also be considered. On sloping sites planting on contour (following the lands natural curves across the slope) can mitigate erosion and runoff, therefore maximizing the absorption of rain and nutrients which would normally be lost. This water will be caught and stored in the hedgerow root systems and released at a slower rate, though this process works best on soils which are rich in clay or organic matter.

In conjunction with riparian planting, hedgerows reduce the flow rate of water into waterways. This lessens the amount of flooding downstream and also has a valuable role in reducing the amount of pollutants and sediment that reach the waterways, through acting as a physical barrier, increasing infiltration into the ground and absorption through the plants.  

Read more on Hedgerows here.

In drought conditions well established trees have the ability to draw moisture deeper from the ground, helping them to survive longer than the shallow rooted plants. They have a cooling effect on the landscape, lowering the moisture loss to evaporation or drying winds and prevent soil loss to wind erosion while the soil is bare. Fodder species provide highly nutritious feed for your livestock while the pastures struggle to grow. Tree fodder trials have shown that cattle in drought conditions can continue to thrive if fed daily on pruned tree fodder. This feed availability continues through into autumn and winter at low pasture growth times if the right tree species for your area are planted.

Read more on Feed diversity for livestock here.

Shelter is another primary reason to ensure your property has adequate trees. This can be in the form of wind and rain shelter or shade. Any plantings done for wind need to be well thought out and a graduated planting is the best form for both filtering and lifting wind up and over your buildings, gardens and orchards. These types of wind shelter take up more space than the classic single tree row shelter belt but are more effective and can be multipurpose with the right selection of trees and shrubs. The single row shelter belts will create wind dumping unless you create an appropriately spaced grid as orchardists do. Shade throughout the hot months should be provided for your livestock and if it can double as rain shelter even better. Anyone who has shelter in their paddocks will have observed how much the animals use it, just because many farms throughout our country have no shade or shelter does not make it best practice. Planting trees in elevated areas or on flattish to low sloping ground, allows for cooling breezes underneath and dryer standing places in wet periods, creating more functional shelter for livestock. In the absence of trees, banks or man made shelters can provide the necessary shelter and shade.

Woodlots or plantings for firewood and/or timber are a necessary inclusion on your land, even if you have a lot of firewood trees now. As these trees are removed, they need to be replaced for future generations of firewood. But this does not mean we need to plant acres of gums, in fact depending on your location this could be a bad idea as gums are hungry trees which don’t give back to the land and if not harvested in time can become very dangerous and difficult to harvest. There are many more beneficial trees which can be grown for firewood or timber, and which can be coppiced. This means you can cut the tree at a younger age, and it will regrow from the trunk, producing multiple stems to be harvested again. These trees can be included in your hedgerow, shelter, riparian or woodland plantings making them multipurpose.

Read more on Coppiced Woodlands and The Sustainable Firewood Woodlot.

Your fruit and nut trees can provide firewood too from their pruning’s as well as feeding your family and your livestock. Utilising food producing trees in the wider landscape can support the feed requirements of your animals especially if running pigs or poultry.

But future proofing also involves mitigating risks, proximity of plantings to buildings, power lines, drainage/septic pipes, fences and access ways need to all be considered. This does not mean trees within these areas need to be removed but they do need to be maintained or monitored. Learning correct pruning methods helps reduced damage or die back on trees which need pruning. Making sure you have the equipment needed to clear any branches or trees which do fall and repair fences where necessary. New plantings can be back spaced from hazards to their potential future height distance or potential root spread if pipes or roading are nearby.

By observing your landscape and choosing plants which suit your climate and desired outcomes you can create a highly beneficial and productive addition to your property. But also build your properties resilience for the future.

The Argument Against Pines.

As our government pushes for much of our country to be planted in forestry we see, in some areas, that the damage caused by pine trees has been catastrophic. What this highlights is the need for being aware of your landscape and planting the right trees for your location and requirements. Pines have in many cases been planted in unsuitable locations for their rapid growth here in New Zealand, the proximity of the trees to one another does not allow for sturdy spreading root development and as they become top heavy, they are a massive hazard. In a study carried out by a regional council, they concluded that ‘Common barriers limiting the development of a deep rooting system include a permanent high water-table, bedrock depth or a cemented iron pan, stoniness, and depth of colluvium.’ This is what we have witnessed in our high rainfall environment with its shallow hillside soils. While the trees in their younger years may have added stability to the hillsides, as they grew and neared harvest age, they become unstable and any high rainfall or wind event not only results in trees being uprooted but also in the tops snapping. This was especially bad during harvest time as trees which had previously been protected by windward plantings were now exposed to the full onslaught of the winds. Any wind event brought a domino effect of falling pines, often across our gravel road. Cyclone Gabrielle blasted through our partially harvested valley leaving a trail of destruction in her wake. Whole ridge lines of trees where leveled or left as broken shattered trunks. This also occurred in forested areas on the National Park to Turangi road, where most of a mature forest block was virtually leveled. There have been cases of this happening amongst native forest plantings too but they are much rarer. If planting a plantation forest is something you are considering please look at the higher value timber tree options and find one that is suited to your landscape.