Invasive Rhododendron in Woodlands – a Permaculture Approach

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Introduced to Britain by the Victorians, Rhododendron has become a very popular garden plant. Unfortunately however, one particular strain, rhododendron ponticum, has become invasive in British woodlands.

The plant tends to crowd out all other species, diminishing biodiversity and destroying the ecosystems which normally thrive in woodlands. They prevent light from reaching the woodland floor and can grow as tall as trees, the weight of their entangled branches even pulling trees down.

Many different approaches to controlling rhododendron have been tried throughout the UK. One approach is herbicide, in particular glyphosate weedkiller, which is injected into the rhododendron stems after drilling or sprayed onto young foliage. This approach is extremely expensive and leaves glyphosate residues in the soil. It also leaves a forest of dead rhododendron plants which in itself doesn’t necessarily result in the restoration of woodland ecosystems.

There is the ‘lever and mulch’ method, which aims to kill rhododendron without the use of herbicide. This method can be effective but is very labour-intensive and again does not let light in to the woodland floor for ecosystems to regenerate. Using machinery to shred and crush rhododendron has a similar result, and is very energy-intensive.

Valley Wood has just such an invasive rhododendron problem. But the more time I spend there, and the more I work with the landscape and the existing ecosystem, the less satisfied I have become with these traditional approaches to rhododendron control. I started wondering what a Permaculture approach to the rhododendron problem might look like.

The basic premise of traditional control methods is that rhododendron is an invasive alien and must be killed, uprooted, cleared completely from the site and surrounding areas in order to allow the indigenous woodland ecosystem to regenerate. Although some of the neighbouring woodland plots have had this treatment, the rhododendron has come back again, and it very soon became obvious to me that this kind of approach just could not work at Valley Wood.

So I started to do some research to learn more about rhododendron. Since it was so plentiful and tenacious, I wondered if a Permaculture approach would allow me to turn a problem into a benefit and begin to view it as a crop of some kind.

Rhododendron was originally introduced into some woodlands because it is a very dense, evergreen shrub, which meant that it provided excellent cover for game birds. Now, this property of course has not gone away, so I immediately realised that one good thing about my woodland is that there is ample cover for birds all year round. Many insects can be found on the rhododendron too – every time I work at clearing some of it, there is always a Robin following me around picking insects off the cut stems. It’s actually quite enjoyable to have some company while I work – I feel like the Robin is working with me, and getting his dinner at the same time. Some of the rhododendron plants are so huge and dense that it can feel quite magical walking around underneath them, like being in some kind of weird twisted fairytale forest.

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So, the birds like it. And as it happens, so do the bees! Around May to June, when the rhododendron is in flower, there is an amazing display of huge purple flowers which provide large quantities of food for bees and other pollinating insects. This isn’t necessarily good for humans – honey made from bees which have been feeding on rhododendron flowers is actually poisonous and can make you quite ill! But for a couple of months at least, bees will be glad of the display. With the changing climate, I have even seen some rhododendron plants flowering in the autum, winter and spring.

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Another property of rhododendron is that it makes excellent firewood – even when it is green. It is a fast-growing hardwood with a very high calorific content, and the stems of larger plants are so thick that they can easily be sawn up into logs which are perfect for either an open fire or a wood burning stove. I have taken rhododendron logs home to burn in my woodburner during the winter, but a particularly good use for the rhododendron firewood is on-site, where I need to keep warm during the winter when I am there working. Burning rhododendron means that I can generate firewood as I am clearing the rhododendron from the woodland, meaning that I don’t have to have a big stack of it seasoning and I don’t have to cut down broadleafed trees and season them for use as firewood on-site, I can leave them standing and growing. So rhododendron has become my staple firewood, leaving the trees for better purposes.

Here are some rhododendron stems ready to be cut into lengths for firewood:-

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The smaller twigs and branches I tie into bundles with string, and one bundle makes a perfect firelighter. The dry twigs catch light incredibly easily, and the rush of heat is plenty to get bigger logs and branches burning. So butchering and using the different parts of the plant gives me everything I need to keep warm when I am working at the woodland. One of the principles of Permaculture is that everything has its place in the system – and the system at Valley Wood includes me, the woodland manager, and rhododendron to provide firewood to keep me warm. The rhododendron has gone from being an alien species which requires total eradication (impossible and a huge ongoing effort) to being a fast-growing hardwood wood fuel which keeps me warm even as I clear it to let light through to the woodland floor. A Permaculture approach where nothing is wasted, and everything has a function.

Even having found a place for rhododendron in the Valley Wood Permaculture system, there is far too much of it, and large areas need to be cleared to allow the woodland to regenerate. Once I’ve started cutting into an area of rhododendron, what is left looks very barren and bleak, as can be seen from these photos:-

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In the photo above, you can see the normal woodland floor ecosystem in the foreground which has regenerated after rhododendron clearance – lush with moss, ferns, foxgloves and all manner of other plants and fungi. The newly cleared area in the background is barren, although there are seeds lying dormant in the ground. I sometimes assist the regeneration by sowing a mix of woodland flower seeds onto cleared areas.

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In the area above, one effect of the huge rhododendron plants was that there were many trees which had grown very tall and spindly instead of bushing out, as they grew towards the light competing with the rhododendron. When I cut the rhododendron down, the weight of the branches pulled down many of these trees. But I found that what I had ended up with was a lovely collection of long, straight poles, perfect for shelter building! So I cut the fallen trees off at the base and used them. With sunlight now coming through to the woodland floor, the cut stumps will start to grow again, giving an area of hardwood coppice. In the photo above, you can see some of the tall, pole-like trees still standing in the background.

Whilst cutting rhododendron stems for firewood, occasionally I would come across one which was nice and straight, or curved in quite an interesting way. I started to wonder whether they would make good walking sticks. A few years back I bought a set of whittling knives, so I thought I would have a go at making a few rhododendron staffs.

I found the wood very pleasant to work with, the bark has an almost reddish tinge and the wood underneath it is lovely and white. There is a lot of quartz in the rock at Valley Wood, so I easily found small quartz crystals with which to adorn the new staffs. I found that I really enjoy making them. Apparently rhododendron wood has the property of protecting the staff owner from enemies! I have already sold one of these staffs and hope to sell more as my staff-making improves. And rhododendron wood seems to be an excellent, strong wood for walking sticks!

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One of the ways which rhododendron spreads is when heavy branches bend down and touch the soil, and the branch puts out new roots at the point of contact. Like other hardwoods, rhododendron can be propagated from cuttings, but rhododendron is particularly easy to get to root.

There are a few places in the woodland where I have wanted some kind of screen to obscure the view of the campsite and shelter, or the forest garden. I did wonder about buying a couple of hundred hawthorn whips and planting them to make hedges. This seemed like quite a laborious and expensive option, the hedge would not really be tall enough for a couple of years at least and in the winter it would not serve as a screen as all of the leaves would fall.

Whilst cutting rhododendron, I noticed that after I had separated out the main stems for firewood, I was left with a big pile of branches of three or four nodes, which were very bushy and green – perfect hedging material, in fact. So I decided to take advantage of rhododendron’s easy rooting property, and simply took all of the cut branches and pushed the ends into the ground along the track above the campsite, forming a very dense, very instant and completely free-of-charge hedge!

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Again, using the discarded parts of the harvested rhododendron plant in this way means that nothing is wasted and everything has a use – Permaculture in action.

There are even more uses for rhododendron – the leafy stems can be harvested and sold to companies providing foliage for florists. There are a couple of reports which make very interesting reading regarding generating an income from rhododendron:- Profit from Rhododendron and Rhododendron Foliage Harvesting.

My aim with Valley Wood is to eventually clear most of the rhododendron from the woodland, allowing the woodland ecosystem to regenerate. But in the process I will benefit from firewood logs, kindling, poles for building, free hedging and the rhododendron plants I leave in place will provide cover for birds and screens. I think that the Permaculture approach to rhododendron control says that although the plant has come to Britain as an invasive alien species, it is here to stay and must find its place in a balanced system. Left to its own devices in the wild, it will upset the ecosystem balance, but as part of a managed Permaculture system with humans included, it has a place as a productive plant which is kept under control by regular harvesting for its products, with no need for the damaging use of herbicides or energy-intensive industrial clearing efforts.

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Insulation Upgrade – A Range of Ideas

I was recently working out the carbon footprint of Green Cottage, and came up with a very favourable figure of less than one tonne of CO2 a year – this being associated with the grid electricity I use. I’m with Good Energy who use 100% renewable energy, but for the purposes of counting I take the figure for normal grid electricity as that’s what comes to my meter.

I was quite pleased with this – but the figure doesn’t tell the whole story. My heating in the winter is wood fuel, and in a cold winter I tend to use a LOT of it – maybe 6 tonnes or more during one of the bitterly cold winters we had a couple of years back. I don’t really feel comfortable with this – for a terraced house it seems excessive, and unsustainable.

The way to get fuel consumption down is of course by improving the thermal insulation of a house. I have a particular problem in that I live in a solid-walled Victorian end terrace, which means that it’s not possible to insulate the walls as they don’t have a cavity which can be filled in the normal way. And because I live on the end, the gable end wall is big and cold and not insulated by a house next door.

The government is hoping to remediate homes such as mine through the new “Green Deal” scheme. Under this scheme it is intended that homeowners can get a whole-house retrofit. In my case this would mean either internal insulation on all of the walls, or external cladding. External cladding could be a problem as for a terraced house you have to persuade all of your neighbours to have it too before you can get it done, and also being on the end overhanging the pavement, the council might refuse permission as the insulation would remove some of the pavement space and so be a ‘land grab’.

Getting internal insulation done for the whole house under the “Green Deal” could also be problematic – it would mean that I would have to move out, really, whilst the work was done. Also, my kitchen and bathroom would have to be ripped out and reinstalled, and it’s not clear at the moment that the “Green Deal” would pay for this. And finally, I would end up with a loan repayable through my electricity meter, at 7.5% interest.

These problems will be encountered by many people in my situation. I had a good think, and decided that I would tackle some of the main insulation problems one at a time, with the hope that all together they would make a big difference to the thermal comfort of my home and fuel consumption.

The first thing I decided to do was to upgrade the insulation in the loft – this would be easy and cheap. I had already had 270mm of glass fibre insulation installed through an energy company discount scheme. I decided to upgrade this to 420mm – apparently 500mm is the Scandinavian standard for loft insulation. I used a product from B&Q which is 55% sheep’s wool and the rest is recycled plastic bottles. The insulation cost around £12 a roll and I used about 8 rolls.


The second job I decided to do was the bathroom, which is a cold room on the corner of the house. Even though the window is double glazed, the glazing is quite old and when in the bath or the shower I could feel a draught coming off the window. So I decided to put an extra layer of glazing in myself, which I did with perspex sheeting and magnetic tape, sealing around the edges with a window silicone sealer. The secondary glazing has made an absolutely huge difference. It cost me about £120.

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To add extra comfort to the room, I wanted to add an extra heat source. There is a small towel radiator in there plumbed into the wood burning stove, but it’s not enough to really keep the room warm. As it’s a bathroom it wasn’t possible to use an electric heater, and I didn’t want a big clunky gas heater in there. In the end I opted for a bioethanol fire, at £70. The fuel comes in plastic bottles and the fire costs about £1 per hour to run. A single fill will last about 2 hours which is enough to warm the bathroom up before I have a bath or a shower. The fire produces a little bit of water vapour but nothing compared to what the bath or shower themselves produce! So an ideal solution for the bathroom. I put the fire on a spare roof slate.

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The kitchen window behind the sink is of the same type as in the bathroom, and is similarly draughty. On the kitchen window I decided to try a cheaper solution, which I got the idea for from @JoRichardsKent on Twitter. I bought a roll of bubble wrap intended for insulating greenhouses during the winter, and made a 6-ply pad out of it to fit onto the back of the window. I used clear sellotape to make the pad, and attached it around the window with gaffer tape. It still lets light in, but of course is opaque with the bubble wrap, but on this particular window it doesn’t matter too much as I have a blind in front of it anyway. The bubble wrap works really well and cuts down the draught massively! It cost about £12 for the roll of bubble wrap.

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The most expensive and ambition measure I’ve added though is some internal wall insulation on the gable end wall in my bedroom.

I decided to make a wooden frame on the wall to hold panels of ‘ecotherm’ insulation – a PIR rigid insulation board of the type commonly used in building modern relatively well-insulated homes. I used 75mm thick panels.

A professional doing this would have removed the radiator from the wall, and re-plumbed and re-attached it once the wall had been insulated. However, being an amateur and not being able to be bothered with draining the system and all the rest of it, I decided instead to make a box around it, and line the box with reflective foam in order to make sure that all the heat from the radiator comes into the room and doesn’t go on heating the wall behind it.

Once I had attached the insulation to the wall, I screwed plasterboard over the top and added a layer of plaster, and then painted it. I used buckets of ready-mixed plaster as I’m an amateur. The finish was a bit rough but after I sanded it and painted it white, it now looks quite attrative and ‘cottagy’. The wall insulation, plus the extra insulation in the loft, has made my bedroom toasty warm, a huge difference. Insulating this wall cost me about £500 in materials altogether.

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I had a few insulation panels and some bubble wrap left over, which I used to completely fill in my spare room window – it’s not often used and it’s the only room in the house where the window is still single glazed. It’s dark in there now but of course has an internal light for when it’s needed. This has stopped the room from sucking out precious warmth from the rest of the house.

These various measures, put together, have made a huge difference to the energy efficiency of Green Cottage. I’m hoping to carry out some more improvements in future, with maybe more internal wall insulation, thermally lined curtains and other measures. But this shows that tackling a range of small insulation jobs can be affordable and have a disproportionately large benefit on the overall comfort and efficiency of an old home.

UK Fossil Fuel Subsidies

There has been much discussion in the press and blogosphere recently about an OECD report on the ‘levels of subsidy’ enjoyed by fossil fuels worldwide, broken down by country.

The report, which counts tax breaks as a form of subsidy, calculates subsidies to fossil fuels in the UK at around £3.6 billion in 2010. Most of this ‘subsidy’ comes from a preferential VAT rate of 5% on domestic energy supplies, as opposed to the normal 20% for goods. Other tax breaks include relief on certain ‘economically marginal’ North Sea fields. North Sea oil and gas is heavily taxed and raises a large income for the Treasury. This is justifiable as the oil and gas are UK national resources and belong to the UK rather than to the oil and gas extraction companies. The Treasury’s policy has been to adjust the tax regime so that extraction remains profitable whilst maximising income to the Treasury.

The Guardian has calculated the level of subsidy for renewable energy at £1.4 billion for that year. Renewable energy subsidies are not largely a result of tax breaks, but a result of an obligation on energy companies to invest in renewable energy through various schemes such as the Renewables Obligation and the Feed In Tariff. As they do not come from the public purse, renewables subsidies can be regarded as an additional tax on energy companies. This impacts on profits but some have argued that the cost is automatically passed onto the customer. The profit regime of energy companies however remains opaque.

Energy companies are not necessarily oil companies, but for the sake of argument let’s say this leaves a net difference of around £2.2 billion in subsidy for fossil fuel industries.

Some commentators argue that this calculation is not correct as tax relief on an already very high tax regime cannot be counted as a true subsidy. Normally this reasoning would be correct, but in this case fails to take into account that North Sea oil and gas reserves are property of the UK and not property of the oil and gas companies. Failure to recognise this fact would be to provide a subsidy to the oil and gas companies of free oil and gas, both very valuable exhaustible resources. In contrast, wind and sun (and wave and tidal energy) actually are free, and inexhaustible.

This difference is key. The costs of renewable energy are the equipment used to harvest these free fuels (i.e. wind turbines and solar panels), and research and development. These costs are likely to naturally fall over time, and indeed have been doing so, even as efficiency rises. Conversely, as the finite reserves of fossil fuels become depleted, the market price of energy derived from fossil fuels will rise, as it is indeed doing, along with the costs of extracting them as the ever more difficult resource deposits are tackled. Tax relief given by the Treasury is based on the costs of extraction of ‘difficult’ fields – the Treasury however has no control over international oil and gas prices, which remain at record highs despite worldwide economic recession. In theory, the rising market price itself will eventually make economically marginal oil and gas fields viable. So why does the Treasury need to give additional tax relief? Simply, to bring the exploitation of these fields forward in time. The subsidy is being paid by the future UK economy for the benefit of the current government.

The same will apply to the “generous” tax regime that the Chancellor has said he will put in place for the exploitation of ‘shale gas’.

Wind and sun however will continue to be free into the foreseeable future. Subsidies given now to improve and bring down the cost of the harvesting technologies will result in permanently lower energy prices.

Green’ groups have seized on these figures as evidence that fossil fuels have an unfair market advantage, even without considering the contribution of additional carbon dioxide emissions to the increasing amounts of heat energy being held in the Earth’s atmosphere, resulting in a more energised biosphere and resultant climate impacts, as forecast by climate scientists.

Of course, climate science is in its relative infancy and it is notoriously difficult to predict localised weather, so the amount of environmental and economic damage resulting from the burning of fossil fuels is difficult to quantify. Lord Stern estimated in his review that the world could lose around 10% of GDP through the effects of climate change, with a 50C rise in global temperatures (currently predicted by the World Bank, amongst others) – around £243 billion annually if translated to the UK. If correct, this economic cost represents a subsidy to the fossil fuel industry as the industry does not have to pay to rectify the environmental damage its pollution causes. Of course, this figure for the UK is the cost of global emissions, not just UK emissions. UK emissions are about 1.75% of the world total, so we would be responsible for around £4.2 billion of that annual loss.

One indicator of whether or not climate change is actually having an economic impact is the reinsurance industry. In many US states, insurers must disclose to financial regulators their exposure to climate change related risks. Here in the UK, the government is currently in difficult negotiations with insurers to try to retain insurance for domestic homes at risk of flooding. 2012 has been one of the worst years in living memory for flooding.

So whilst statistics about individual storms, droughts etc are debateable and contentious, the insurance industry whose business it is to know about risk and put a price on it, is raising costs. These higher insurance costs also represent a subsidy to the fossil fuel industry.

Support for the fossil fuel industry could be a risky investment for the UK, according to the Bank of England. Tax breaks now to encourage the development of marginal oil and gas fields could be wasted if the future value of these resources disappears. Oil companies can write off the cost of establishing production from an oil field against tax immediately rather than over the lifetime of the field.

Back in November 2009, Andrew Mitchell MP gave a passionate speech to the Overseas Development Institute pledging to end the Labour Party’s support for fossil fuel projects across the globe, citing support amounting to three quarters of a billion pounds. He was absolutely clear that climate change is one of the major risks to humanity. Yet here in 2013, on the website of the UK Export Credits Guarantee Department, is listed support of $1 billion for Petrobras offshore oil and gas projects.

If the tax revenue from oil and gas was being used by the Treasury to reduce demand for energy through a programme of energy efficiency, then that would be a justification for continuing to develop fossil fuels. However, even the revenue from carbon taxes such as the CRC Energy Efficiency Scheme is not spent on improving energy security for the UK.

So it does seem clear that UK fossil fuel companies do receive significant subsidies which are not afforded to renewable energy, for extremely questionable benefits, except the short term financial interests of the current government and the oil and gas companies themselves.

Whilst renewable energy does not generate an income for the Treasury except for normal corporation tax (which, after tax breaks, is often all oil and gas companies end up paying on the marginal fields which are left to exploit, effectively giving away the resource itself free of charge), it increases UK energy security whilst ensuring long-term lower energy prices for consumers, as well as giving the UK the opportunity to become a world leader in the development of efficient technologies.

By contrast, the fossil fuel extraction industry has a finite lifetime which is increasingly beset by rising costs, technical difficulties and environmental risks, not to mention the obvious geopolitical destabilisation that political reliance on fossil fuel producing countries brings.