We planted our first wood in 1978. These were not just pre-Internet days. Back then even tree tubes hadn’t been invented.
As far as I can remember we followed a conventional method in attempting to establish a deciduous wood, using Sitka spruce and Scots pine as a nurse crop, to be thinned out once the oaks and other broadleaves got into their stride. All of the trees were planted six feet apart, roots tucked into notches cut into the turf.
The conifers established fairly quickly but the oaks were lamentably slow, struggling to compete with the vegetation which threatened to swamp them. We could not have used herbicides even if we had wanted to, without risk to the trees themselves.
Five years later we moved to Airdlin Croft, from where we can see our first wood which, from a distance of 1.5 miles looks like a conifer plantation. Unfortunately we have not had the opportunity to revisit, even though we did offer to undertake maintenance work free of charge.
Our second wood was planted in 1990. Once again we were keen to establish native broadleaves, but by then the plastic tree shelter (or tube) was available, which eliminated the need for a nurse crop of conifers and facilitated wider planting spaces. So this time we installed a separate block of conifers – equal numbers of Scots pine and the non-native European larch which we intended to thin out at a later date. These were planted without protection.
Tree tubes offered the following advantages: at 1.2 metres high they protected the young saplings from both roe deer and rabbits; they functioned somewhat like individual greenhouses, protecting the emerging trees to some extent from wind and frost damage (which impacted heavily on our 1978 efforts); and they facilitated the use of glyphosate to control weed growth over the first two or three seasons.
The results were impressive. At least 95% of the trees prospered and today many of them have reached 50 feet in height.
The tubes that we used back then were manufactured by a company called Argival Plastics, and didn’t stay on the market for very long. Constructed from a thick, corrugated material they were virtually indestructible and unless removed, using a very sharp knife, they could end up strangling the new tree. We lost one or two that way. But we also discovered that the tubes which had been slit from top to bottom could be used again, despite a certain loss of structural integrity.
However, when we engaged in our third major tree-planting effort in 2015 to establish a shelterbelt around two new acres of garden, we bought the latest types of tree shelter, designed to break up when the tree expanded within. We used the short, net tubes for the conifers (unavailable in 1990) and the 1.2 metre ‘solid’ ones for the broadleaves. But this time we employed a different planting technique, using our micro-digger to strip off a rectangle of turf and break up the soil beneath, before planting and tubing the tree and then mulching with woodchips. No herbicides were used.
The results were more than impressive, with some of the new trees growing so fast that the top growth could not be supported by the embryonic root system, resulting in more than a few blown over in strong winds. Another six went that way just yesterday (7/10/19).
Some species have suffered more than others. Of the broadleaves, silver birch (Betula pendula) has fared worst, victim of its own rapid growth rate. One or two rowans (Sorbus aucuparia) and Norway maples (Acer platanoides) have also succumbed, while the slower-growing oaks (Quercus robur) have remained upright. Of the conifers, European larch (Larix decidua) has proven to be the most susceptible, with little damage to Scots pine (Pinus sylvestris) and none to grand fir (Abies grandis).
Thus in both categories, as might be expected, it is those species with initial fast growth rates that have incurred the greatest loss. While the tube, anchored by its stake, offers all the advantages listed above, it also prevents the ‘wind whipping’ process that seems to encourage adequate root development, creating a dangerous imbalance between top growth and underground development.
I say loss, but the collapse of a tree does not necessarily guarantee its demise. Of the six that fell over yesterday – four larches and two birches – five either broke their ties or stakes and only one snapped at the base. The two birches were re-staked; and three of the larches were amputated a few feet above the ground, leaving some needle-bearing branchlets to support regrowth.
Obviously an amputated tree will fail to become a stately specimen, but in a shelterbelt a bushy, multi-stemmed plant may actually be more useful. An arboricultural friend has suggested that amputation could save more trees than might be conserved through re-staking. Though it is quite hard to take a saw to a new tree.
So – to tube or not to tube? That is the question we have been debating as we attempt to fill the gaps in the shelterbelt and interplant amongst a collection of exotic oaks that is struggling in our harsh climate. Our decision not to use plastic shelters this time is based on the following considerations.
First of all, we are engaged in a general attempt to use less plastic. However, a range of biodegradable, non-plastic tree guards is becoming available; and where appropriate we are re-using old plastic tubes that have been removed without destroying them.
Secondly, grazing pressure in this new two acres is minimal, as the entire area is fenced against roe and rabbit. This hasn’t prevented rabbits from gaining access, via badger holes or gates inadvertently left open; but at this moment in time, we are fairly sure there are none inside this fence. Voles cannot be fenced out and this year seem to be particularly numerous, causing some damage to unprotected plants; short tubes, or cut-down re-used tubes, minimise such damage. In our opinion, the 1.2 metre tube is only worth using if roe deer are a problem
Third, the tree-planting method recently adopted, using digger and mulch, ensures that the new tree avoids damaging weed competition in its early years and gets off to a very good start.
Also, many of the spaces have been filled with some of the hundreds of birch seedlings generated from the 1990 wood and which we observed to be largely untouched by the rabbits that live in wilder parts of the garden.
In conclusion, it must be acknowledged that tree tubes can be very useful (as can the Internet…) - on unfenced sites, on poorer soils and with species that grow relatively slowly. In such circumstances, we would use them again.