Saturday, 23 July 2011

Cidre Trees, Windbreaks & Landcare. We Need to Get Involved & Rethink

I don't think UK farmers are planting enough new trees on their farms. On a recent UK “Pasture to Profit” discussion group study tour of Brittany with a group of pasture based dairy farmers I could help but be impressed with the relatively new Tree rows or farm hedges that some of the pasture based dairy farmers in Brittany were planting. They are quite different from what is commonly seen on English farms. The hedges consist of a number of different trees but also included both flowering scrubs & even fruit trees. These new & very attractive farm hedges/windbreaks were taller & more open than most hedges in the UK.
They were more effective windbreaks, less annual work to manage & aesthetically very attractive.

Do we have enough trees on our UK pasture based dairy farms? Are our hedges very effective? Is there an opportunity here to add to the biodiversity on our farms?
The answer I think is NO, NO & YES.
I’m not suggesting the traditional hedges be ripped out as they are an important part of the UK agricultural landscape & this working industrial landscape is hugely important to our heritage & the tourism industry.
However compared to other agricultural nations the present farmers are planting very few new trees. I think this is both a problem & a lost opportunity. Take the Landcare movement in Australia for example. Most Australian farmers belong to their local Landcare group & most Australian farmers are actively planting thousands of trees. We should be doing this here in the UK. Why don’t we start a Landcare UK group in every rural district in the country? Pasture based dairy farmers could lead these groups to make sure they were effective & productive groups.
On of the on farm features in Brittany are the trees & scrubs planted into an earthen wall called a "Talus".
The planted talus--a steep earth berm (an earthen mound often between a road/track & a drain), planted with beeches, oaks, or hornbeam--was traditionally created to delimit the boundaries of farms in both Brittany & Normandy.
That's why, if you drive the country roads of the region, you often find your path "sunken" between two steep berms crowned with magnificent beech trees and flanked with a thick tapestry of ferns, vines, and wildflowers. The durability and beauty of this peculiar landscape feature has prompted me to reflect on its use in the UK as a farm shelter hedge. In many ways it is very similar to the hedge rows of Devon & Cornwall that are built on top of an earth mound between the road/tracks & a drain on the farm side of the hedge. These farm hedges in Devon & Cornwall are not recent structures but have been built generations ago.
The talus consists of a packed earth berm say a 1-1.5metres high, half a metre wide at the top, and with sides sloping at a steep angle of 60 degrees. The top of the talus is planted with closely spaced trees in a single row or--more frequently--in an offset double row. The trees are set on approximately 4-foot centres. I know this may seem like impossibly close spacing, but such close planting is integral to the success of the talus, ensuring that a dense network of roots retains the soil of the berm. And believe me, it works. Many examples of talus hundreds of years old, crowned with magnificent towering beeches, bear testament to the validity of these living architectural farm structures & why there has been a recent surge in their use on dairy farms in Brittany. A new generation of pasture based dairy farmers who are not only very conscious of the beauty of their environment but who are keen to increase the biodiversity of their farms, are leading the charge.
The advantages of a talus are that it alone provides shelter for live stock especially calves, there is very good drainage for the trees & scrubs & the bulk of the talus is top soil so it’s an ideal medium to establish trees & a farm hedge.
Effectiveness of Windbreaks & Hedges.
Windbreaks are designed to break up the wind energy/power to provide a more pleasant environment for pastures & livestock on dairy farms. Historically hedges determined farm & field boundaries but today they provide shelter of a sort to livestock especially young calves & milking cows. Are they very effective at providing shelter….probably NOT. There are two major limitations, firstly height & secondly they tend to be near solid structures (density greater than 80%) so they change the dynamics of the wind but do little to provide shelter. In fact they probably increase the wind speed over and around the hedge.
As wind blows against a windbreak, air pressure builds up on the windward side (the side towards the wind), and large quantities of air move up and over the top or around the ends of the windbreak. Windbreak structure -- height, density, number of rows, species composition, length, orientation, and continuity -- determines the effectiveness of a windbreak in reducing wind speed and altering the microclimate. Windbreak structure -- height, density, number of rows, species composition, length, orientation, and continuity -- determines the effectiveness of a windbreak in reducing wind speed and altering the microclimate. Height is a very important factor in the effectiveness of a windbreak/hedge. On the windward side of a windbreak, wind speed reductions are measurable upwind for a distance of 2 to 5 times the height of the windbreak (2H to 5H). On the leeward side (the side away from the wind), wind speed reductions occur up to 30H downwind of the barrier. However this is influenced by the density. So a density of 40-60% is the most effective at providing downwind area of protection. A density under 20% is ineffective & as already discussed over 80% is a problem. The link between effective windbreaks & pasture growth is well established as it influences temperature. The calves do much better in a well protected environment.
 If you want to read an excellent guide to windbreak effectiveness I suggest you read this article from Penn State University  
The more species of trees & scrubs in a hedge/windbreak the better as it influences the height & the density. This allows you to add biodiversity to your farm & include flowering species to help our friends the honey bees. I was impressed in Brittany to see flowering scrubs like Hypericum (the yellow flowering scrub in the photos), Buddleja, Rhododendron, Ferns as well as Heritage apple trees.  Why not add apple trees for example that have flowers & fruit that can be harvested….cider is a very nice drop on a hot day & very traditional.
So our traditional hedges in the UK may not be very effective at either providing shelter, windbreaks or adding greatly to the biodiversity on our pasture based dairy farms. This in my view creates an opportunity & the French examples are excellent. Tree rows with many different species of both local trees & flowering scrubs. There is an opportunity begging to grow more cider apple trees as well.
I think the existing pasture groups should be initiating Landcare groups in their local community & taking a positive lead which could have massive genuine PR value in the rural & city population of the UK.
My thanks to my Breton friends Andre, Alain, Yvon & Jean Herve
Current UK Pasture Measurements
Pasture growth across the UK has generally improved if you have had rain but in the Midlands growth still very slow & soils still very dry. Experience suggests that growth takes sometime to get going after long dry spell but once soils are wet it all happens quickly!
TheAverage Pasture Cover (kgsDM/ha) & Pasture Growth (kgsDM/ha/day)
Northern Ireland, Portaferry, AFC 2150, Growth 78, demand 53, cutting silage bales to improve quality. Lots of showers
Cumbria, 2650, growth 77, demand 50, still silage to cut

North Wales, 1963, gr 64, demand 53,
Cheshire organic, 2100, gr 25, dem 25, round 35 days, feeding to hold covers
Shropshire, 2150, gr 35 but expecting growth after rain this week
Shropshire, 1984, gr 32, dem 33, feeding to build covers
Staffordshire, 2232, growth 35
East Staffordshire, 2100, gr 50 demand 35, light rain but not enough yet
Oxfordshire, 1950, gr 20, rain 15mm so optimistic
Dorset organic, 2550, gr 70, cutting wholecrop today
Cornwall Average Farm Pasture Cover 2450, growth 85, demand 58, more silage not enough cows

1 comment:

  1. This is a very helpful French website about the french farm tree rows & the varieties of trees that can be successfully grown. Sent to me by Alain & Odile from Brittany.
    Use the Google translator to read it in English or other languages. Tom