Last tree standing ?
Just as many animal species are threatened with extinction, so are many species of tree. In fact, one estimate suggests that up to a third of tree species are under threat - that is more than 17,000 species. This equates to more that the number of endangered mammals, birds, reptiles and amphibians put together. In 2021, the IUCN (the International Union for the Conservation of Nature) produced a report on some 58,497 tree species which identified 17,510 species as being threatened (and 142 extinct in the wild). In Mauritius, some 57% of tree species are at risk of extinction! Ideally, no single tree species should be lost, a single species can be an integral part of an ecological network. Its loss could result in the disappearance of many species and even an ecosystem collapse. Some tree species are now represented by single numbers of specimens. The ‘lonesome palm’ (Hyophorbe amaricaulis) is probably the last surviving member of its species. It is to be found in a botanic garden in Mauritius. It is an old, damaged and spindly specimen. It has problems with fruit formation; each of its fruits contains but one seed and the seeds are difficult to germinate (even the botanists at Kew could not persuade them to grow). The best approach to saving vulnerable trees is to protect their natural habitats. This might mean controlling grazing by herbivores, or banning logging in sensitive areas. Sometimes a change in cultivation techniques can make a difference. The Lansan Tree produces a valuable, aromatic resin. It is endemic to the Windward Islands and its fleshy fruits provide for native pigeons and other wildlife. The resin is collected (tapped) from the tree by slashing the bark every one-to-two weeks. However, over-tapping for the resin can lead to the trees becoming infected with pathogens, then rotting, or subject to termite attack. The pathogens may spread to untapped trees. Unregulated tapping and conversion of land from rainforest to agriculture have led to Lansan Tree populations all but disappearing in places. On Saint Lucia, where there is a large but threatened population of Lansan Trees, there is hope after the introduction of a sustainable resin harvesting technique. This technique does not damage the tree but still allows a good yield of the resin. This, coupled with training of licensed resin tappers should protect the trees. Some species have reduced populations because their pollinators have been lost, so fruit and seed production has ceased. Other species have separate male and female plants (dioecism) and the small populations that remain are represented by only one sex. This was true for the catkin yew population in Hong Kong, where all the trees were males. A global search found a female specimen in the Royal Botanic Garden in Edinburgh. Cuttings from the Edinburgh tree have now been planted in a managed site in Hong Kong. Hopefully when they flower, fruit and seed production will occur; but it may be a long wait for the young trees to reach sexual maturity. Another species, the oleander podocarp (Podocarpus neriifolius) has been nursed back to viability by similar techniques. Some rare and isolated trees produce seeds but getting them to germinate is another matter. Many seeds enter a state of dormancy and have extremely specific requirements for them to germinate and grow on. In many cases, their needs are simply not known. The seeds may need a particular temperature regime, or exposure to cold, fire, smoke or light of a particular wavelength. Some seeds may need to travel through the gut of a particular animal before they will germinate. Sometimes, scientists have used to embryo culture. The embryonic radicle (root) and plumule (shoot) is extracted from a seed and then grown in a sterile nutrient culture medium. This technique was used at Kew with the ‘lonesome palm’ as attempts to grow its seeds had failed. Embryo culture resulted in plantlets forming but after a while their roots turned brown and the young plants died. There are success stories. A Cypress species Widdringtonia whytei, was reduced to a few trees in Malawi, as a result of illegal logging for timber. Many seedlings have been planted on Mount Mulanje and a good number of these have survived. [caption id="attachment_25196" align="aligncenter" width="675"] Entrance to the Millennium Seed Bank[/caption] When and where seeds are actually available, they can be dried or frozen (cryopreservation) and placed in seed banks, for example the Millennium Seed Bank at Wakehurst Place. We have to hope that through various interventions, the use of seed banks, botanic gardens and arboreta that we will be able to save many rare and threatened tree species, you never know when one might be needed.
woodlands web updates : 28
On the Red List! The capercaillie is threatened. Its numbers in Scotland have roughly halved (between 2010 and 2020). It was once widespread, but now it is found in the pine forests of the Highlands - notably the Cairngorms National Park. It is a red listed species. The decline in numbers is associated with poor breeding success, poor weather in early summer when the chicks are developing, another problem is predation by species such as the pine marten, foxes and crows. The Game and Wildlife Conservation Centre (GWCT) has identified another issue that these birds face - namely collisions with deer fences. These fences are created to keep deer out of particular areas. However, when the capercaillie (and black grouse) impact on these fences, they are injured or killed. Marking these fences, reduces the number of collisions but does not stop them. Unmarked fences are still killing adult birds. Marking of these fences or their removal would help with the survival of the capercaillie, though removal would mean trees and shrubs would be unprotected from deer. Mosquitoes! There are some 36 different species of mosquitoes to be found in the UK, which are generally harmless (though they bite). But that may change. With longer and warmer summers, the UK may become a venue for other species such as the tiger mosquito. This insect has been found in ‘traps’ (monitored by the UK Health Security Agency) at ports and rail terminals. This insect is known to transmit various diseases, such as dengue fever. The mosquito was found in Italy in 1990 and it is spreading on the continent. A species of Culex has also been found in some areas of the Thames estuary - which can spread the West Nile Virus. This virus can result in flu-like symptoms. Outbreaks have been been mainly in the warmer areas of the Mediterranean, but with climate change and the potential for very hot summers here - vigilance will be needed. Floral defences. Many flowers release a distinctive scent. The scent serves to attract pollinators like bees and butterflies, or it may ward off pests that would feed upon the plant.. Many of the chemicals that contribute to scents are terpenes. Recent research has investigated how these chemicals can affect the growth and development of butterflies - using painted lady butterflies. These butterflies feed on a wide range of plants and hence are exposed to a variety of scents / terpenes. For these experiments, the researcher (at the University of Centra Florida) used four common floral terpenes Limonene : which has a fresh, citrus like smell Linalool. : has a floral scent, reminiscent of lavender Cineole : has a camphor-like smell, slightly medicinal contributes to eucalyptus oil. β caryophyllene : this has a spicy / woody fragrance. Different amounts of these terpenes were fed to caterpillars of the painted lady butterfly, and the subsequent development of the caterpillars was monitored and the size of the adults recorded. The experiment was also conducted at different temperatures. Temperature affects scent release by flowers. Higher levels of terpenes has significant affects on the survival of the caterpillars, especially when combined with the higher temperatures. The caterpillars took longer to enter into pupation when given high levels of terpenes, though the size of the adults that emerged from pupation was unaffected. If longer and warmer summers become more common, the combined effects of terpenes and heat could become important determinants of development. `
From meadow to woodland.
Anyone who has worked with us at Hive Cleaning, knows that sustainability is one of our most important guiding principles, along with being an ethical employer and exceptional cleaning standards. We take sustainability ambitions seriously and have reduced our direct emissions to zero and are on track to reach Net Zero in 2025. However, we didn’t want to just focus on our day to day operations (being technically ‘green’) but wanted a direct involvement with nature and natural ecosystems; that’s how our idea of a reforestation project was born. We fell in love with a meadow (near Clovelly, in North Devon), a beautiful part of the world. The meadow has stunning views and we could immediately imagine how tree planting in the meadow could further enhance the biodiversity and beauty of the area. [caption id="attachment_40611" align="aligncenter" width="675"] Hive Wood Sign[/caption] We have renamed Rosedawn Meadow to Hive Wood, and we are planning to plant over eight thousand trees over the next 15 years. As a part of our wider ESG strategy (this documents the company's impact on the environment) , we are committed to : ● Recreate historic hedgerows around the boundary ● Only planting local native broadleaf tree species ● Measuring the sequestered carbon via Carbon Trust ● Never selling the carbon credits ● Never felling the trees (except where necessary in terms of managing the wood) ● Improving biodiversity and creating a haven for flora & fauna ● Using Hive Wood to promote biodiversity and carbon reduction / sequestration. We started the planting the trees and the hedgerow in March, this year. So far, we have planted eight native species: sycamore, rowan, white poplar, sessile oak, buckthorn, black alder, blackthorn and hornbeam.
Woodlands web updates : 27
Tree survival and drought. Researchers at the University of California have been working on a method that helps predict whether forests / woodlands can survive periods of drought. As climate change is altering patterns of snow and rainfall, so periods of drought are likely to become more common. Forests are important in terms of carbon sequestration, that is, they take up carbon dioxide from the air and convert it into sugars, starches etc that are stored in the leaves, branches, stems and roots. However, in order to assimilate and convert carbon dioxide (in photosynthesis), trees (indeed all plants) need a supply of water. When water is limited, trees need to make use of their reserve materials. Just as we make use of body reserves of fat and glycogen when food / diet in inadequate. However, reserves can only sustain a tree for a finite period of time. If drought persists, the tree reaches a ’tipping point’ and it will die. The researchers studied a forest in the Sierra Nevada that experienced a period of drought between 2012 and 2015. During this period, millions of trees died. The team recorded rainfall, soil moisture and temperature in the forest AND the amount of carbon dioxide that the trees absorbed, and their reserve materials. They found that the trees were able to maintain function / health after the onset of the drought but with the passing of time, the trees exhausted their reserves and were unable to use / convert carbon dioxide into food. They had reached the tipping point and died. The methodology of this study was called CARDAMON (carbon data assimilation with a model of carbon assimilation); it is hoped that it can be used to evolve strategies to enhance forest and woodland resilience in the face of climate change. Pollinators. [caption id="attachment_35902" align="aligncenter" width="675"] hoverfly[/caption] University researchers from the UK and Finland have been trying to determine the most effective pollinators of crop plants, like strawberries (and other fruits). Plentiful and effective pollinators are needed to ensure a good harvest of the fruits. The researchers studied the pollinators at three strawberry farms through the (long) growing season for the fruit. They adopted two approaches : They caught the insects that visited the strawberry flowers and analysed the pollen they carried in detail (pollen load and type). They also counted the number of flower visits by the different insects, (a quick way to identify key local pollinators). Many insects were identified, including :- European drone fly : Eristalis arbustorum Honeybee : Apis mellifera Levels drone fly : Eristalis abusivus Buff tailed bumblebee : Bombus terrestris White tailed bumblebee : Bombus lucorum Common drone fly : Eristalis tenax Red tailed bumblebee : Bombus lapidarius Early bumblebee : Bombus pratorum Bent-shinned Morellia : Morellia aenescens Hoverflies are true flies, that is, they belong to the order Diptera or true flies, as they have a pair of wings and a pair of halteres (balancing / orienteering organs used when in flight). Several of the flies in the genus Eristalsis are known as Drone Flies (due to their resemblance to honey bee drones). The larvae of Eristalis species are commonly found in putrid / stagnant water and sometimes referred to as “rat-tailed maggots”. It was noted that pollinators also made use of the wild plants to supplement their diets, as strawberries alone cannot meet the nutritional needs of pollinators. ‘Elsanta’ strawberries have a relatively low sucrose and protein content in both their nectar and pollen. The precise order of importance of pollinators varied between farms. Bee (Apis and Bombus) species and hoverfly (Eristalis) emerged as key pollinators. The European drone fly was the most important pollinator at two of the three farms studied, evidence that hoverflies can be effective pollinators. One farm had commercial hives of the honey bee but they were less significant than the activities of of the hoverflies and bumblebees. The abundance of a particular insect, coupled with its active period were / are important determinants of pollinator importance. Sawdust and plastics - a possible use?. Plastics represent a relatively new, but persistent and major form of pollution (on land, in the sea, indeed everywhere). Whilst many plastic objects are instantly visible in the form of discarded bottles, fast food containers, many plastic pollutants are in the form of very small particles of plastics - nano and microplastics. The concern is that we and other organisms are taking these microscopic particles into our bodies from our food / drinking water. However, it is possible that plant materials may offer some ‘solutions’. Water that contains micro and nano plastics can be filtered through sawdust that has been treated with tannic acid. Tannic acid is large molecule, its molecular formula is C72H52O46 . Tannic Acid is found in certain plant galls (swelling of trees caused by parasitic wasps) and in the twigs of certain trees, such as Chestnut and Oak. The wood sawdust contains fibres of cellulose, combined with hemicelluloses and lignin. Water can flow through this material by capillary action. This plant-based filtration (known as bioCap) of plastic-laden water is capable of dealing with a wide range of nanoplastics (PVC, PET, polyethylene etc), and tests with mice suggest that the filtered water may be sufficiently free of plastic to pose little risk.
Trees – come in all shapes and sizes
Trees come in many shapes and sizes. Some are tall and thin, like Poplars, others have a ‘rounded’ canopy, like oak and horse chestnut. Sometimes we ‘persuade’ trees to assume a particular shape or form, perhaps through pollarding or coppicing - or something more extreme - like topiary or bonsai. However, sometimes nature itself has unusual or dramatic effects on trees. Wind can leave trees on cliff tops or exposed places distorted and growing almost horizontally along the direction of the prevailing wind. Occasionally, something very strange is seen. For example, at Gryfino in Western Poland, there is a forest with some very weird looking trees. There are about 400 trees that are bent at the base. At first, the trunk lies more or less parallel with the ground, then it bends upwards and the stem is erect. Consequently each trunk of these pines trees has a pronounced bend in it (see photo below). The rest of the trees in this forest are quite normal, growing upright and straight - like most pines.It is thought that the pines were planted back in the 1930’s though the local town was forsaken by the residents during the second world war (and only repopulated in relatively recent times). The trees are sometime referred to as the Crooked Forest. There has been much speculation as to how the trees came to be so mis-shapen. The theories run from The landing of alien space craft! This crushed / flattened the trees when young and tender The trees were damaged by German tanks during the war (but why only a select number of trees?) Genetic mutation(s) which resulted in abnormal growth Fungal infection(s) which resulted in abnormal growth The young trees were flattened by a heavy fall of snow, which perhaps persisted for some time. The trees were able to right themselves in the Spring, through a normal geotropic response. The trees were part of plantation / forest, in which some were deliberately cut at a young / sapling stage. The area was a tree farm, where some of the pines were cut / bent for later use in furniture or frames. By bending a young tree down to the ground in this manner (for some time), compression wood is formed. Such wood has higher lignin and lower cellulose content and it is stronger than wood that is bent after a straight tree is felled (for example, by a steaming process). Indeed, English ‘hedgerow oak’ was known to be the best for the curved timbers needed to internally strengthen a sailing ship. Trees were even deliberately bent in certain ways so as to " grow" a required set of curved timbers. Such curved timbers were known as “compass timbers”. In Gryfino, it is likely that the war interrupted the activities of local foresters / woodworkers, they left and these trees were left to grow on in their rather unusual form. Thanks to Kalasancjusz at Pixabay for the image of the crooked forest.
The short lives of many urban trees
The woodlands blog has reported on urban forests, the trees in our cities, lining our roads and in our gardens. This green infra-structure in our towns and cities provides a range of economic, environmental, and social benefits. The importance of green, leafy spaces was emphasised during the early days of the Covid pandemic, helping with mental and physical wellbeing of many people. Urban trees offer Valuable habitats for wildlife and can provide biological corridors / stepping stones that enable birds and other animals to move through the urban environment. Shade and cooling in streets and parks. They can help reduce the risk of flooding, allowing more water to enter the soil rather than running off hard surfaces of tarmac and concrete. The capture of pollutants, improving local air quality by capturing fine particles from the air (mainly through deposition on leaf surfaces). Trees and shrubs seem particularly effective in removing ozone. Through their photosynthetic capacity, trees can take up carbon dioxide into organic form - carbon sequestration. The amount of carbon taken up by London’s urban forest each year has been estimated at 77,200 tonnes. However, recent studies suggest that many urban trees are under threat : Trees are subject to heat stress as many cities experience the heat island effect, the ambient urban temperature is significantly above the surrounding countryside. Many struggle to get sufficient water as they are planted in small square of soil and surrounded by tarmac, concrete or paving stones. Soil compaction is often an issue, affecting water permeability. They may experience an ‘excess of nutrients’ - due to dog’s urine, this is a source of urea and other nitrogen compounds. Once planted, young trees may not receive after-care / management. This point is significant. Many trees die within the first few years of planting. In Boston (USA), some 40% of trees are dead within seven years of planting. Similar figures are true for New York. Both rural and urban trees suffer significant mortality when young but whereas the death rate of rural trees tend to decrease after a few years - urban trees are more likely to die as they age. [caption id="attachment_40541" align="alignleft" width="300"] Young urban tree[/caption] There is a struggle to reach maturity. Most trees need two or three decades to offset the carbon emissions associated with their planting / maintenance etc, and they then sequester carbon at a significant rate. Work at Boston University (in Professor Lucy Hutyra’s lab) and Harvard has focused on the problems that urban trees are facing, and another issue (apart from those mentioned above) has been identified - the microbiome of the root [that is the variety of micro-organisms that surround / inhabit the root tissues]. Urban trees seem to have fewer symbiotic fungi in their root systems when compared to rural trees. Roots often develop mycorrhizal associations with fungi. Such systems allow the roots to access more water / minerals and in return the tree ‘offers’ the fungal network a supply of carbohydrates. Jenny Bhatnagar (Harvard) has investigated the soil microbiome in eight different plots, some urban and some rural in Massachusetts. Interestingly, the investigation found that whilst there were more fungi in urban plots, they ‘seemed more reluctant’ to establish symbiotic associations with the roots of the trees. This failure could be due to the excess nitrogen / nitrates in the soil (from animal urine / faeces?). When there is an excess of nitrogen available, trees tend to dispense with their fungal partners. The hotter temperature of urban soils might 'favour' a bacterial population (some bacteria ‘fix’ nitrogen). [caption id="attachment_40526" align="alignright" width="300"] Once, there was a cherry tree ...[/caption] It is not clear as yet why so many urban trees fail. It could be that the loss of the symbiotic fungi renders the trees more susceptible to certain disease-causing microbes. The hotter and drier soils at the edges of fragmented forests have more pathogens and not so many symbiotic fungi. A number of simple aftercare / management measures would help young trees to establish : Watering the trees in their early years Preventing soil compaction to allow water to percolate, and oxygen to diffuse to the roots. Mulching around the tree base (helps water availability and slows nutrient input from urine etc.) An interesting article on mycorrhizae and urban trees may be found here. [caption id="attachment_40537" align="alignleft" width="220"] Olive[/caption] The importance of soil micro-organisms is also indicated by research in Australia, where shrublands / woodlands have been invaded by African olive trees. The olives have disrupted the partnerships between the Acacia trees (hickory wattle) and symbiotic soil bacteria (Rhizobia ssp). This is another symbiotic association, where the partners exchange materials for mutual benefit, Where the Olives have grown, the Acacia have problems establishing root nodules with the bacteria. To restore these scrublands, a full understanding of the soil / root microbiome will be important. Full details of this work can be found here. Postscript : In today’s Guardian (03/11/2023), Helena Horton’s article “Ministers should target tree survival ‘rather than planting’” reinforces the points made in the blog about the early mortality of young trees - urban or rural. Increasing woodland cover will only occur if young saplings survive.
Plastics and tree guards
Plastic is a problem, plastic is universal. A class from Ramsbury Primary School went on a walk round their village, looking for signs of plastic pollution. When they looked in the hedgerows (lining the paths and fields), they found old plastic tree guards (and hedge guards). Some were breaking up into pieces, some growing growing into the bark of the trees. In addition, there were plastic bottles, face masks, dog poo bags, sweet wrappers, plastic ropes, plastic bags, and plastic wrappers from hay bales. Plastic litters our world. Each year, hundreds of million tonnes are produced. It is used but often it is not recycled - it is discarded. It litters the land, rivers and oceans. It is now almost impossible to walk in the countryside or on a beach without encountering plastic in one form or another. Discarded plastic can kill or injure. Mammals, reptiles, birds can be harmed through eating plastic or becoming entangled in it. Plastics are made up of repeating units (monomers) that join together to form long chains (polymers). There are six major polymer types, PET, HDPE, PVC, LDPE, PP and PS. Many are derived from petrochemicals. Additives are incorporated into plastics and these can gradually leach back out either during normal use, or when in landfills, or following improper disposal in the environment. Whilst plastics serve many different functions, their makeup means that they do not easily break down, they persist. Consequently, a lot of plastic goes to landfill or it may be burnt (to generate energy) - which in turn can release greenhouse gases and pollutants. Ideally plastics would be reused, like glass bottles were recycled in the dairy industry for over a century. Polyethylene is used widely for plastic bottles and food packaging, PVC is used to make pipes (for water / sewage), coating for electrical cables, uPVC windows and fascia boards. Recycled PVC can be used to make certain types of tree guards, for example :Spiral guards. Such guards offer protection to young trees and hedgerow so that they can establish themselves, avoiding being chomped by rabbits, deer or sheep. The guards also offer a micro-climate that helps growth. UV stabilised polyethylene is used to make netting / mesh to protect young trees. [caption id="attachment_34477" align="alignright" width="300"] Tree guards, to protect young trees on moorland[/caption] Tree failure can be an expensive process, so it is important to give young trees a ‘good start in life. A ‘weed’ free area around the planted tree reduces competition for water, light etc. In theory, it should be possible to reuse plastic guards, but they are often damaged, degraded or have to be cut to remove them from the young tree. As they are not biodegradable, it is important that they are collected and removed. Ideally this material should be recycled. If many trees are being planted, it may be simpler / more cost effective to fence off the planted area to protect young trees from browsing activity. Because of the problems associated with plastic tree guards, there are now a number of alternatives available. For example, wool-based tree guards / shelters (eg. Next Gen) are fully biodegradable being made from wool A biodegradable polyol made from ethically sourced cashew nutshell liquid and castor oil A polymer that breaks down over time Other biodegradable forms of tree protection make use of a polymer made from sugar cane (eg. HyTex products). Such guards decompose slowly through the action of microbes (bacteria and fungi), temperature and humidity, gradually forming a compost - so their removal is not needed.
Bees, agrochemicals and the microbiome
Mason bees and agrochemicals The blog has reported many times on the threats to bees - money bees, bumblebees and ‘wild bees, such as mason bees / solitary bees. The threat to bees from neonicotinoids has been well documented, now there is a report that suggests that certain other agrochemicals may be harmful to bees. Researchers at the Julius Maximilians University at Würburg have been investigation the effect of a fungicide (Fenbuconazole) on the reproductive behaviour of horned mason bees (Osmia cornuta). A number of Osmia species are used to improve pollination in fruit and nut crops. They are efficient pollinators having a special pollen collecting / carrying structure called a scopa. Mason bees are solitary bees. Each female is fertile and makes her own nest and no worker bees for these species exist. In the Spring, male and female bees emerge from a nest. The males generally exit first and remain near the nest, ready to mate with the females. A female bee selects a mate on their ‘smell’ / odour and the ‘quality’ of their thoracic vibrations (achieved through muscle contractions). After mating the males soon die. The females search for and select a nest site, visiting flowers to collect pollen and nectar for their nests. Once a certain amount of food has been collected within the nest, the females lay their eggs on top of this material (in a series of cells) and then seal off the nest. The eggs hatch to form larvae which feed upon the food and within weeks forms a cocoon, in which it continues to develop to an adult. Though the fungicide (Fenbuconazole) is considered to be of low toxicity and the bees were exposed to a sub-lethal dose, nevertheless the Fenbuconazole had significant effects on the bees. Pesticide exposed males were more likely to rejected by the females, compared to ‘control’ bees that were not exposed to the fungicide. The thoracic vibrations of the exposed males were less powerful / noticeable and the composition of their odour or smell was different. The smell of the bees is dependent on particular hydrocarbon compounds in their cuticle - their exoskeleton. It is possible, therefore, that the mating behaviour and reproductive success of these bees is being affected by agrochemicals. Carpenter bees. The microbiome refers to the collection of micro-organisms that lives on or in us, particularly within within the gut. Whilst these micro-organisms are small, they contribute to our health and ‘well being’. They offer protection against pathogens, help our immune system develop, and enable us to digest. Just as we have a microbiome so do bees. Scientists as York University (Canada) have been investigating the microbiome of three species of carpenter bees (from North America, Asia and Australia). The term "carpenter bee" comes from their nesting behaviour, most species burrow into plant material such as dead wood or stems, though a few create tunnels in soil. Social bees (like honeybees and bumblebees) acquire their microbiome by interacting with their hive or nest ‘mates’. Solitary bees, like the carpenter bees, get their microbiome from the environment as they forage for food. The researchers found that: The bees’ microbiome contained Lactobacilli, which are important for good gut health, helping protect against fungal pathogens and facilitating nutrient uptake. They also discovered crop pathogens in the microbiomes of the carpenter bees which were previously only found in honeybees. Whilst these pathogens are not necessarily harmful, it is possible that the wild bees could be vectors for spreading disease. With thanks to Pixabay (Umsiedlungen and Sabinem34) for the above images of bees Finding flowers. Research at the University of Exeter has shown that bees can distinguish between various flowers through a combination of colour and pattern. This selectivity is achieved despite the ‘acuity’ of a bee’s vision being quite low (about a 100 times lower than ours) - this means they can only see the pattern of a flower when they are quite close (a matter of centimetres). The researchers analysed a significant amount of data on plants and visiting bee behaviour, and they used experiments involving artificial shapes and colours. One particular finding was the importance of the contrast between the outside of the flower and the plant’s foliage. This seemed to help beesfind their way to the flowers quickly .