Big trees, little trees, can they compete?
Site and the correct choice of fruit tree
Tree height restrictions and how to deal with them
Renovating neglected orchards
Trees and flooding
Big trees, little trees, can they compete?
Perhaps you already have healthy, well-established trees in your garden, and you want to fill a gap with a new tree. In this case, you have to follow a certain procedure to give the new tree or trees a chance to compete successfully with the trees already there, and ensuring them a constant supply of moisture, light and nutrients throughout the growing season. Here we go:
1) Choose the correct fruit type, rootstock and variety compatible and vigorous enough to compete with the already established and larger trees in close proximity.
2) Use a mini digger to prepare the planting hole, and cut and remove all the roots of surrounding trees that are crossing the planting hole. The size of the planting hole needs to be 1 metre square and 45 cm deep. (If you don’t have a mini digger, well, it’s going to be spade work… take your time, take it easy, do some warm-up exercises before you start. If you have back or heart problems, ask someone who is fit to do it… or hire a mini-digger.)
3) Next, loosen the subsoil but do not take that soil out of the planting hole.
4) Remove and cut back all overhanging branches of other trees, which will be taking away the light of the tree or trees to be planted.
5) Mix plenty of garden compost or well-rotted straw-based farmyard manure into the soil.
6) When planting your trees make sure the union of the trees is at least 4 inches above soil level once planted.
7) Plant the trees well away from any building or wall, which might create shade.
8) Firm the soil around the roots, but with only moderate force. No stamping. Stake the trees with a 6 foot, circular-section, 2” diameter stake, which has been treated against fungi. If it is not treated against fungi, it may rot off at soil level.
9) During the growing season do not forget to water the trees weekly, with 10 litres of water for each tree.
10) Apply “Growmore” spread evenly over the 1 square metre area, twice a year, in February and June. Do not allow any weeds or grass to grow on your specially-prepared soil area, around the trunks of the trees. Mulch the trees if possible. Follow instructions on the fertilizer packet. Do not exceed the stated rate of application.
If you do all the above you will succeed. Good luck and all best wishes!
Site and the correct choice of fruit tree
To create a successful multi fruit orchard, it is very important to carry out the various soil preparations during summer or early autumn. The winter months, the correct time to plant fruit trees, are often not good for soil preparation, as the soil is already too cold and handles badly. The quality of the soil in the planting hole will determine how quickly and how well the newly-planted tree settles down in its new home.
The rootstocks that you will be using depends on the space available for planting fruit trees. Dwarf rootstocks are recommended when limited space is available. If a good deal of space is available, then the trees would do best if planted on semi-vigorous stock such as MM106, Quince A and St Julien A. These trees need to be planted approximately 3.5 to 4 metres apart. The exact number of trees needed also depends on the proximity of other large trees, such as hedgerow trees, oak, ash and sycamore. Fruit trees do badly when planted on the live roots of other trees. Follow this link to find out more about tree size and rootstocks.
I think that it is a good idea to set out the orchard before the planting season, initially using 6-foot tall bamboo canes. This way you can mark the planting spots of your new trees, in relation to hedgerows, buildings etc.; it gives you an idea of how the new multi-fruit orchard will look. Variety choices can only be made once you have decided which type of fruit you want to plant. Follow this link to view a list of fruit tree varieties.
The ideal pH of the soil is 6.3 to 6.8. Outside those limits, nutritional deficiencies will occur when the trees get older. Fruit trees love well-rotted good organic stable manure, provided straw is used as a base material and not sawdust or wood chips. The more manure you can work into the ground during the summer months, the better the trees will perform in years to come.
Open sites without any protection against strong winds may be OK in the South of England. However in the North of England and Scotland, where the temperatures are already lower and the winds even stronger, compared with the South, the tree may survive, but regular crops are unlikely to be achieved.
However it is amazing what can be done if some sort of shelter is available, such as planting along a south or east-facing wall or behind a tall hedge or a row of trees acting as a windbreak, for the area where the fruit trees are planted. However leave enough room as a headland, as fruit trees do not like to grow in the shade of other taller trees, neither do they like being planted on top of live roots of existing trees in the surrounding area.
It is of great importance that where winds can be strong, the trees are properly staked and well secured with an adjustable tie. The stakes need to be planted in an upright fashion and be 6 foot in length and round with a diameter of 2 inches.
Unless planted in a walled garden, the best rootstock for open sites is MM106.
Secondly, valleys collect cold air and often lead to spring frosts at the time fruit trees are in blossom. The prospects of a decent crop diminish with every spring frost in the period from late March to the end of May. For that reason try to plant further up the slope, where the air is warmer.
If there is a hedge or a dense row of trees that stops the cold air from draining away, a 3 to 4 metre gap should be created at the lowest point in the hedge.
Summarizing, fruit trees do best if planted at a site with a good micro climate of relative warmth and shelter. Valleys collect cold air and are therefore risky sites for fruit trees. This is linked to the possibility of serious frost damage to fruit tree blossoms in the period from April to May.
Tree height restrictions and how to deal with them
Many people with newly-built houses or allotments are keen to grow fruit trees along their border line or separating fence or wall. But often they run into a problem: due to legal restrictions or rules, the trees are not allowed to grow any taller then 6 feet.
In this case, it is best to follow a modified planting procedure:
1) in the case of apples use the rootstock M26,
2) in the case of cherries use the rootstock Gisela 5,
3) In the case of plums, the rootstock Pixie is not always suitable,
4) In the case of pears, use a root control bag.
An alternative method is also available. Use an 16 to 18-inch clay pot or plastic pot with good drainage holes. Sink the entire pot into the soil with the rim of the pot protruding above soil level by 1 inch, and plant the tree in the pot. This will prevent the tree-roots escaping over the top of the pot. To stop the drainage holes getting blocked by roots in future years, it is essential to cover the drainage holes with broken bits of terracotta pots or the equivalent. Blocked drainage holes kill trees!
This method will effectively reduce the root run. This in turn will limit the tree height to around 6 feet. However, if this method of growth control is chosen, it is most important that the trees are routinely watered once or twice a week depending on weather conditions.
Another method is to use a root control bag. These are suitable for all types of fruit trees. These bags reduce root circling and result in an altogether more fibrous root system. Excellent root bag products are obtainable from:
Renovating neglected orchards
New owners of a property that includes an old orchard are often faced with this question: is it worth the time and finance to renovate a neglected orchard? Even when taking out of the equation the value of the site related to other considerations such as, for example, house building, careful thought has to be given to the problem before undertaking such a major operation. The chances of success are not always very great. The following questions will have to be asked:
1) Why did the orchard become neglected?
2) Which rootstock was used for the trees?
3) At what distances apart were the trees planted in relation to the rootstock used and the quality of the soil?
4) Is the soil free draining?
5) Are the fruits of the varieties of interest to you, whether for sale or family consumption?
6) Could the fruit be used for processing?
6) What is the rating of the site in relation to the risk of hail?
8) Are there any difficult diseases in evidence, such as canker or Armillaria root rot or collar rot?
Often, if fruit trees become neglected, and they are planted in deep, free-draining soils, the task of renovating the orchard – which includes bringing the trees down to a manageable size – is particularly difficult. The main reason is that one has to deal with the very powerful root systems of healthy trees. Often the root systems are larger than the trees themselves.
Therefore hard pruning is usually not a successful way of dealing with the problem. In short the renovating process will have to be spread out over a period of 3 to 4 years. Even so at the same time one has to do everything possible to keep the trees cropping well. This is of great importance because to control tree size, it is important that a major part of the tree’s energy resources is used in fruit production and not for surplus wood production.
In summary, the questions listed above have to be looked at first of all. Only after having determined the answers can you make a realistic risk assessment. The outcome of the overall risk assessment evaluation will determine if renovating the orchard will be worthwhile.
The positive effects of a medium-density shelterbelt on orchard productivity and regular cropping
A good windbreak is a very profitable investment in relation to the productivity of an orchard in England. The main reason for this is that fruit set is significantly increased, particularly in years when during the blossom period the weather is cold and the wind is strong. This better fruit set is achieved as a result of the warmer microclimate amongst sheltered fruit trees. The net effect of a better fruit set is even more important in years when blossom is not abundant. This can be caused by several factors. However in practice the main reason for scarcity of blossom is caused by over-cropping in the previous year. Another instance when the level of fruit set is of major importance, is when an April or May spring frost has killed off many blossoms. The remaining undamaged late-developing flowers will be the only ones left which can secure a crop of sufficient volume to be of commercial interest.
A very important factor is that the windbreak should be of medium density. For example, windbreaks of pine and/or fir trees are far too dense. These windbreaks cause strong air turbulence and therefore diminish the positive effects of a well-positioned windbreak. Ideal for an orchard is a windbreak of birch trees. These trees by nature reduce the wind strength, instead of stopping the wind all together just behind the windbreak. Poplars, willows and alders have the disadvantage of blocking drainage systems in orchards. Moreover the vigour of these trees is often too great, thereby reducing the productivity of the fruit tree rows closest to the windbreak.
The next point to consider is how far into the orchard does a windbreak make a difference to fruit tree cropping. Research workers have found that the optimum effect is found over an area 8 times the height of the windbreak. In other words, if the windbreak is 10 metres in height, then the area of orchard receiving the highest benefit is that within 80 metres from the windbreak. Beyond the 80 metre point there is still an effect, but at a reduced level. The strongest effect will be found in the area of 4 times the height of the windbreak.
Another point which needs to be taken into consideration is that without insects, the quality of pollination is greatly reduced. Wind pollination is only effective when the climate conditions are such that the humidity of the air behind the windbreak is sufficiently high to make germination of the pollen possible. If the stigma is too dry then the pollen is unable to grow down the pollen tube of the flowers and therefore fertilization of the egg cell cannot take place. Without this fertilization process, no fruit growth can be achieved.
From the above statement it follows that everything must be done to attract beneficial insects, bumble bees and honey bees. The orchard environment has to be made attractive to insects so that they find it a suitable habitat in which to live throughout the year. This is particularly true for the period when blossom is over. A perfect combination capable of achieving this particular requirement is to plant a wild flower area in or around the orchard. The flowers in the wild flower mix are very important. Ideally there should be flowers open from April until November. In that way, beneficial insects and various predators will help create a natural balance, keeping the various species of pests under control. This will help the orchard to flourish in as natural an environment as possible.
Pollinating insects are more frequent visitors in well-protected orchards, particularly when temperatures are low during blossom time. Strong drying winds and salt-laden winds are often the cause of low fruit set and poor fruit growth. Also it has been established that fruit trees form fruit buds more easily if the area where the fruit trees are planted has the benefit of increased temperatures as a result of the wind reduction effect. Again, the best way to achieve this is by a row of birch trees, planted at the edge of the orchard.
Fruit size will also improve, as long as sufficient soil moisture is available.
My experience gained over many years growing various fruit crops and selling top quality fruit trees has highlighted various changes in the insect and bird population in and around orchards. These changes are also occurring in gardens, in spite of the fact that the micro-climate in gardens is often far more amenable for many insects and birds when compared to commercial orchards. Good pollination for many fruit crops is vital for regular crops. Without the help of pollinating insects, regular crop production is a frequently-occurring problem. The problem is that most fruit crops flower early in the growing season, when it still can be very cold and wet. These are not the climatic conditions favourable or liked by many pollinating insects.
Due to many factors, cherries, plums, greengages and pears, to name just a few, all flower from the middle of April onwards. This is a general statement. I have seen that when conditions are warm early on in the season, in February/March, these fruit trees begin to flower by the end of March/early April. But where are the pollinating insects such as bumble bees, hover flies and such like at that time of year?
Honey bees are often only around in low numbers early in the season. This is due to the fact that the honey bee is not likely to come out of the hive when the temperature is below 16 degrees Celsius. The bumble bee however is fully active from 10 degree Celsius. For good cross pollination we therefore have to rely on insects such as the bumble bee, when the weather is too cold for the honey bee. If nothing is done to encourage these wild pollinating insects to do their vital cross pollination work during their quest for food in the form of nectar and pollen, the fruit trees in question are unable to produce enough fruit. Both yield and quality will be reduced.
This is why the establishment of wild flower areas is vital. Particular attention must be given to the choice of various flowering species. There has to be a regular food supply, in the form of flowering plants throughout the growing season. That means from March to some time in September. Only in this way lots of pollinating insects are attracted to build their permanent homes, in the immediate areas where pollination activities are needed, such as orchards. In our experience a combination of annual single blooms and regularly flowering shrubs is possibly the best method of providing adequate food for the pollinating insects.
Another point is that it is better to have lots of flowers of a few species such as Dog daisies, primroses, lavender and clover, than a much extended range of species with just a few flowers on each shrub or annually flowering plant. However overall the most important requirement is to provide, for the full length of the growing season, enough flowers of plants and shrubs which are able to supply nectar and pollen, so badly needed for the insects to survive during the winter months.
To provide some specific examples, good shrubs for attracting bees and butterflies are:
Buddleia, Lavender, Honeysuckle, Rosemary herb, Ivy, Lilac, Privet, Elderberry, and Buckthorn. Most herbs are very attractive to bees.
Examples of permanent wild meadow flowers, liked by pollinating insects, are:
Clovers, Vetches , Cowslips, Primroses, Dog daisies, Yarrow, Yellow rattle, Knapweed, Red campion, Meadowsweet, Plantain, Angelica and red clover.
Surrounding hedges with Blackthorn and Hawthorn , Bramble and Dogrose are very good for hover flies.
To summarize, orchards are often a mono culture of species. Without a full complement of pollinating insects the fruit-setting capability of fruit trees is very erratic. Therefore a wild flower area with the right type of plants and shrubs is not only very attractive to look at. It also provides a balanced approach to the local environment as a whole.
Click on the thumbnail below to watch the video of this wildflower meadow:
Caring for a wildflower meadow
A wildflower meadow is an interesting project if you have the space. The wildflower meadow that you can see in the photos was initiated in 2000. We sowed grass and a perennial wild flower mix. Soil should not be fertilized, and it should be of poor vigour. Otherwise, grasses will grow too strongly.
Mow in mid-late August; leave the grass there for a few days to allow flower seeds to drop. Then remove the hay.
Repeat every year, sowing new varieties as desired.
It is a good idea to keep a diary of your meadow, recording what you have sown and what has grown. Often what is planted or sown doesn’t appear the next season, but only after a couple of years. Sometimes it appears, but in a different place with respect to where it was sown. The balance of grasses and flowers varies from year to year, affected by climate and presumably by various other factors.
By way of example, here are the species that we have observed over the years in our wildflower meadow in Suffolk.
Lots of grasses
Tiny field vetch
Birds foot trefoil
Geranium (small flowers)
Plantain (several species)
White bee orchid
Trees and flooding
We have heard and seen so much about the dreadful floods all over the country. Nothing is worse than having your house and home standing in water, due to rivers bursting their banks, due to vast amounts of unprecedented volumes of rain. This made me think how people had to cope in Holland with rising water levels of the North Sea after violent storms from the north-west, some 800 years ago. Their main concern and top priority was to safeguard the home and the shed for the domestic animals, a few cows, pigs and chickens. These small farm steads were situated as totally isolated buildings in the middle of lots of low-lying surrounding fields. The surrounding fields were mainly grassland for their cattle. What they did was to build terps (artificial mounds), by hand and a wheelbarrow. They built their home on top of this mound. Obviously in most cases today this is not possible due to a host of environmental regulations. However it is still possible, under similar threatening conditions, to surround your home and garden, with the aid of a JCB, with a dike, wide enough and high enough, to keep the water out. The surrounding dike can be stabilized further by planting fruit trees on the top of the dike and a mixed hedge at the bottom. These will help keep the soil together. Cover the soil with deep-rooting grass to anchor the soil all over the area. Keep some sheep to utilize the grass and there is your personalized flood defence.
Soils and essential preparation for successful growing
Soil is the home of the fruit tree, and as such, everything possible should be done to make it as pleasant as possible for the trees to live in and happily produce crops for the next 50 years or so. A basic error is made by just digging a hole and shoving the tree roots into the hole, covering them with soil and forgetting about it. In most cases this will lead to great disappointment, with trees desperately struggling to survive.
Fruit trees are very sensitive. Particularly the first year after planting. Usually if planting is carried out correctly, then the first step has been made to ensuring that the trees do well. It is often forgotten that the parts of the tree below ground level, the roots of the trees, must be able to function effectively in order to support the numerous demands of all the remaining parts of the tree above soil level.
Fruit trees can be grown successfully in any soil. As long as it is possible for the roots to take up water and the basic nutritional elements such as N, P and K, plus the trace elements, then the fruit tree can establish itself. The soil’s organic content is of great importance. Without the cooperation of various beneficial micro-organisms surrounding the root tips, uptake of nutrients will become impossible. These micro-organisms work best if the soil has a good level of organic matter. All types of well-matured farmyard manure are a real stimulus for all-round good development of tree growth and regular cropping.
Therefore a permanent soil mulch is of great importance. This needs to consist of disintegrating materials such as old wet hay or straw. Or better still, farmyard manure. This will have to be topped up on an annual basis to a minimum thickness of 4 to 5 inches. It should be applied around the trunk of each tree covering a soil area of a minimum of 1.5 square yards. It is of great importance that the mulch remains largely weed free and therefore is of 100% benefit to the tree and not the weeds. Leave a small ring around the trunk free from mulch as the trunk must remain dry and not permanently damp. This helps prevent fungi infections of the trunk. Pears and apricots produce better-sized fruits if fed organically. The ideal time of the year to apply this type of manure is in November. This gives the worms plenty of time to start working the manure into the soil. Then by about next April the trees are already beginning to benefit.
Secondly, roots cannot grow without energy. This energy is provided by the 21% oxygen in the air. From this it follows that it is essential that the drainage of the soil is working reasonably well, particularly during the winter months. Roots standing permanently in water, as a result of impeded drainage, are death to a fruit tree. Particularly during the winter months, roots have to grow significantly. This can only happen when sufficient oxygen is available in the rooting area. Therefore, improve the drainage if it is suspect. If for whatever reason the oxygen of the air in the rooting zone is suppressed, trouble will be brewing. If soil compaction is the cause of limited oxygen supplies around the roots, the tree will be struggling throughout its life. It will be subject to tree diseases such as canker. This in turn will greatly reduce the life span of the tree, apart from a serious reduction in the keeping quality of the fruit.
Lastly you will have to stake each tree. In some soil types, surface rooting of the trees is very important.
Cherries require more soil depth than any other fruit tree. If you are in doubt about the depth of your soil, start by planting apples, pears and plums. In the first growing season you will have the opportunity to observe the behaviour of these trees. Then, according to the knowledge gained, you can the plan next year’s plantings.
If you live in a location with soils where rhododendrons and azaleas do well, it is important to test the acid level of the soil. Fruit trees will do best with a pH of 6.3 to 6.6 . Outside these parameters, the uptake of certain nutrients may become a problem. It is easy to determine the pH of the soil. In good garden centres for little money you can purchase a pH meter.
Regular nutrient application
Most soils will need regular applications of nutrients. Fruit trees do best in the long run if the soil nutrients are applied in the form of organic manures. Additional foliar feeding will be very helpful if certain elements are short. This is not a regular occurrence if the soil has been looked after over many years in the past.
Pure sandy soils are often problematic for fruit trees as their water-holding capacity is very low. At the other end of the scale, heavy clay is a difficult type of soil for roots to develop well. The closer the soil is to a deep loam the better the trees will perform. These soils will hold a lot of water between the soil particles. This is of great importance particularly during droughty conditions. After all, water is the life blood of the tree. Without sufficient water the tree will die.
A quick method of finding out whether the soil is suitable for fruit trees
We often receive questions about whether the soil is suitable or unsuitable for planting fruit trees. The most important thing is not to plant in soil subject to waterlogging, because standing water is highly detrimental to trees. To be sure, dig a planting hole right away to a depth of about 8-10 inches. Wait for 24 hours. If the hole does not fill up with water in this time, you can go ahead and plant the tree.
When planting, always make sure that crumbly soil is put on top of the roots, not big lumps of clay! If necessary, you can use John Innes soil-based compost number 3.
It is essential to use a rabbit guard to prevent animal damage to the trunks of the trees.
If the hole that you have dug has filled with water, don’t despair, there is a method! One system is to plant trees on a mound. The mound should be at least 10 inches in height above soil level and at least 3 feet in diameter. Only use the best topsoil to construct the mound.
Difficult climate and soil
Here are the main rules to follow if climate and soil are difficult:
1) Apples and plums are the hardiest fruit types.
2) Always plant at least 2 of each to ensure good cross fertilization.
3) Do not rely solely on self-fertile status. Even self-fertile trees do better if they have a suitable cross pollinating mate.
4) Make intelligent use of any type of wind break. Insects and birds, essential to fruit trees, will visit at crucial times.
5) Give the trees a chance. Don’t choke the roots under a carpet of grass and perennial weeds.
6) The trunk of the tree is the main transport channel for the supply and delivery of water and food to each part of the tree. Protect the trunk from damage caused by cattle, deer, rabbits, mice etc.
As the volume of fruit grown commercially in the UK is nowhere near enough to satisfy demand, the departure of the UK as a member of the European Union is likely to cause a rise in prices for fruit in the shops. It is therefore very important that fruit trees in the garden are healthy and have a structure such that a good proportion of the fruit can be picked from ground level. This is perfectly possible provided the basic facts of crop rotation are not ignored.
For example we must remember that if an old apple tree is grubbed because it has reached the end of its life, then we certainly can plant another fruit tree on that spot, but not another apple tree. Crop rotation does not only apply to vegetables in the garden. It also applies to fruit trees. In other words, apple after apple or pear after pear is not to be recommended. If this is done all the same, replant disease will probably badly affect the new tree, and the growing and the cropping of the tree will be a disappointment. And yet it is so easy to achieve good growth and cropping of new trees. Just plant a pear or a plum or a cherry at the place where the old apple tree spent its time of life and all will be well. Water the young trees weekly and the trees will have a very good start in life. Particularly if well-rotted farmyard manure or garden compost is applied as an extra tonic.
Weather factors affect the choice of trees. For example, in the northern counties, climatic conditions are substantially different compared with East Anglia. The average temperatures during the growing season are 2 to 3 degrees lower. This results in a shorter period in which the fruit has to mature and develop its full flavour. The same applies to the West Country; here the rainfall is substantially greater compared with the east of the country. Some well-known varieties of apple trees are not suitable for high rainfall areas. Other apple tree varieties are very suitable and excel.
Usually in the UK, winter frosts are not sharp enough to seriously damage fruit trees. It is the spring frosts, particularly in the months of March, April and May, that can seriously diminish crop prospects depending on their severity. The types of fruit that flower earlier compared with apples are most at risk. However in a garden environment it is possible to protect the blossoms from frost damage by covering the trees with a double layer of garden fleece. This should be done in the late afternoon. The fleece has to be opened during the day to provide an entry route for the bees to carry out cross pollination.
Drought, wind and hail
Another weather problem is drought. Light sandy soil can cause difficulties. In these cases it is important to apply extra water, weekly, during the growing season. Water must be available to the trees to create new growth and mature ripening fruits.
Strong winds are often the cause of blackened leaves and fruits. Particularly in the more northerly counties and areas close to the sea, consideration should be given to planting a shelter belt to diminish damage to trees and fruit. A walled garden environment is another option. Good staking will be essential for best results.
Hail can be very damaging during the growing season. Avoid planting in areas known as hail belts.
Type of fruit planted
In warm and sheltered positions in the UK, any type of fruit can be planted. If conditions are different, the earlier-flowering fruit varieties should be avoided in the more northerly counties. Specialist advice is a way of avoiding disappointment.
Prolonged periods of rain can be the cause of various fungal diseases such as scab and tree canker. It is best to use varieties with a reasonable level of resistance to these diseases, rather than chemical spraying.
High levels of rainfall can cause problems if they come at a time when large amount of oxygen are needed in the soil. If soil drainage is not efficient in the soil where the fruit trees are planted, the trees can literally drown. Where there is excess water around the roots of the trees, the oxygen-bearing air is driven out of the soil and the roots die. The effect will not be visible immediately. However, as soon as droughty conditions return, the symptoms will be clearly visible: shoot die-back. More seriously, the trees’ immune system will have been seriously damaged. This means the trees will be an easy target for all types of fungal diseases, such as tree canker, armillaria root rot, crown rot, silver leaf, just to name a few.
Summarising, the soil is the tree’s home. It pays handsomely to ensure that all surplus water, up to a depth of 2 feet of soil, can drain away without any hindrance. Air can enter the soil again and all will be fine.
Trees as long-range weather forecasters
In the winter months, we are usually busy lifting trees and despatching them to their purchasers, and so we regularly inspect the roots of hundreds of two to three-year old trees. From the appearance of the roots, we can judge the period of dormancy of the trees. According to conditions, this period can change, from November to March, or from December to April, for example. But curiously, the exact dormancy period does not seem to depend on the conditions previously, but rather on the weather and temperature in the months to come, so that the tree starts preparing for the spring in advance as if it knew exactly when the temperatures would rise.
I should start with a bit of background information on how the roots work. The feeding roots – tiny and delicate capillary roots invisible to the naked eye – operate from April to September. Then they begin to shut down, and the tree stores resources in the trunk and main root stems. At a certain stage, usually in mid January, white roots begin to emerge from the main root stems. These are not functional as roots, but just serve to establish the initial structure from which the feeding roots will develop. It is the arrival of the white roots that provide an indication as to how long the winter conditions are going to last.
It’s as if the trees know that there is no point in developing their root system yet, because the weather is going to be colder than usual over the next couple of months. How do the trees know this? Perhaps they have a sensitivity to certain meteorological parameters that enable them to time the moment at they begin preparing for the end of dormancy. I am convinced that the world of plants still holds a lot of mysteries that still await scientific explanation.