The opening of the woodland canopy.
Certain woodland plants are found in the understory. Plants like wood anemones, woodruff and lungwort bloom early in the year. These plants make use of a ‘window of opportunity’ when the light levels are good as the tree canopy has not developed, the leaves have not yet expanded. They use this ‘window of light ‘ to flower. However, climate change is affecting many ecosystems - including woodlands. With warmer temperatures, leaf buds tend to open earlier and the leaves begin to expand. If the window for growth is reduced, how can the wood anemones and others cope ? [caption id="attachment_38093" align="aligncenter" width="700"] wood anemone[/caption] To investigate this question, scientists based the Universities of Tübingen and Frankfurt examined thousands of preserved herbarium specimens of early flowering plants, dating back over a hundred years. The sheets not only hold specimens collected when they were flowering but also have information on ‘when and where collected’. Each sheet is a a moment in time from over a century ago. Collectively, the 6000+ sheets allowed the scientists to establish historic flowering times of woodland plants over large areas of Europe. [caption id="attachment_38094" align="aligncenter" width="700"] Woodruff[/caption] The information extracted from the herbarium records revealed that plants like wild garlic and wood sorrel now bloom some six days early than at the beginning of the twentieth century. For each 1oc rise in (Spring) temperature, their lowering has advanced by more than 3 days. This means that they have gained time in the light - in an open canopy. Whilst they may have gained time, these early flowering plants are at greater risk of frosts. It may also be that their pollinating agents may not be around - unless they too have brought forward their development / life cycle. There is some evidence that such changes are taking place. Recent work at Wytham Wood (outside Oxford) has shown that blue tits have moved forward their egg laying to 'match' the development of the oak canopy, and the appearance of caterpillars (on which the young are fed). Essentially, the timing of the food chain has changed.. Hopefully, such changes will occur in different ecosystems across the country.
Making walking sticks – from stems picked out of the woodlands
Woodlands.co.uk is 'republishing' this blog, as contact details for the Jones family are now available and several people have expressed an interest in having a walking stick 'custom made'. The blog originally appeared in 2014. Contact email address is pj451324(at)gmail.com Peter Jones and his sons make walking sticks on a serious scale using sticks they come across in the woods, where they do their forestry work. They use chestnut, silver birch, oak and hazel. But they avoid using willow, as it goes brittle once it's aged. Apart from finding the right stick to work on they need a steamer for bending the tops of the walking sticks and a good supply of sealant and varnish for protecting the finished sticks. "Honeysuckle makes the best twist sticks" advises out Peter Jones, who comes across a lot of twisted stems in Kent and East Sussex. As a result, he is able to trade these with fellow stick makers in more northern English areas - they give him carved tops for walking sticks in exchange for good twisted shanks. But even among twisted sticks there is variety: the slower growing trees such as holly and oak twist more slowly whilst the fast-growing chestnut twists quickly. Though he also corrected me pointing out that the maker of walking sticks should really be called a "stick dresser" Read more...
woodlands web updates 16
LASI is the Laboratory of Apiculture and Social Insects at the University of Sussex. It is particularly noted for its research work on bees. Recently, Dr Balfour and Professor Ratnieks have published a study on the rôle of certain 'injurious weeds'. Five of our native wildflowers fall into this category : Ragwort (Jacobaea vulgaris), Creeping or Field Thistle (Cirsium arvense), Spear or Common Thistle (Cirsium vulgar), Curly Dock (Rumex crispus), and Broadleaved or Common Dock (Rumex obtusifolius). They compared the ragwort and the thistles with plants like red clover and wild marjoram (often encouraged / sown on field edges etc).. They found that the 'injurious weeds' were particularly 'effective' at attracting pollinators, not only did they they attract greater numbers of pollinators than clover etc, but also a greater range of pollinator species. This was ascribed to the open nature of their flowers and their generous nectar production. This brings into question the control of species like the ragwort, as it is clearly important to pollinators (as are some 'botanical thugs' - like brambles). Ragwort contains chemicals that are toxic to livestock, causing liver damage; it has been blamed for the deaths of horses and other animals. At the Smithsonian, Kress and Krupnick have analysed the features of some 80,000+ species of plants to see how they might fare in the Earth's changing climate (the Anthropocene). This may seem like a large number of different plants, but represents approximately only 30% of the known species of vascular plants. There is not enough information of the remaining species to make a reasonable guess as to how they might react to climate change; a reflection on how little we actually known about our 'botanical resources'. Sadly, they conclude that more plants will lose out than win. Particularly at risk of extinction are the Cypress family (which includes the redwoods and junipers) and the Cycads, whereas black cherry might be a winner. As was reported previously in the woodlands blog, there is a difference between the leaves of the redwoods found at the top of the tree and those lower down. Those at the top are small, thick, and fused to the vertical stem axis; this fusion of leaf and stem creates a relatively large volume of tissue and intercellular space that can store water. The leaves in the lower part of the crown by comparison are large, flat and horizontal to the stem axis. Now scientists as the University of California (Davis) have further investigated the role of these leaves. They now believe that the different leaf forms help explain how the exceptionally tall trees are able to survive in both wet and dry parts of their range in California. In the rainy and wet North Coast, the water absorbing leaves are found on the lower branches of the trees. In the Southern part of the redwoods range, the water collecting leaves are found at a higher level to take advantage of the fog (and rain, which occurs less often).
A problem with plastic.
In the C19th, many objects were made from ivory. The ivory came from the slaughter of elephants. As elephant populations fell, so the search for a suitable substitute began. Celluloid was one of the first materials used but it was easily combustible. It was soon replaced by other materials like Bakelite, this was the first entirely synthetic plastic. It was made from phenol and formaldehyde. It was used for toys, radios, telephones etc. Bakelite was tough, heat resistant and did not conduct electricity. Other materials followed, and many different plastics are produced today; for example, polyethylene (which is widely used in product packaging) and polyvinyl chloride [PVC] (which is used in construction and pipes because of its strength and durability). The trouble is that plastics are just so useful. Plastics are cheap, lightweight and durable. Durability is a good quality when the plastic is being used but not when it is discarded, for example, into landfill where it may take centuries to degrade. Sadly, many consumers leave empty bottles / containers / wrappers in the streets, on the beach, at picnic sites etc. As most plastics are made from fossil fuels / oil, the manufacture of plastic is also a driver of climate change. Since the middle of the twentieth century, it is estimated that some 8.3 billion tonnes of plastic has been produced. Sadly much of this has ended up in landfill, in rivers, the soil, and the oceans - with significant effects of wildlife. Plastic pollution is ubiquitous. For example, the Great Pacific Garbage Patch, which is a collection of large areas of plastic and other debris in the North Pacific Ocean. It has been estimated that it contains some 1.8 trillion pieces of plastic . It is a serious threat to marine life such as whales, sea turtles, fish, and birds. Plastic items are discarded with little thought to the consequences. Bottles etc can end up as traps for many animals and a few years back we (at woodlands) found a child’s plastic boat dumped in a woodland (see featured image above). Sometimes, we see the distorted remains of plastic tree guards ‘strangling’ young trees. Plastic carrier bags (sometimes filled with dog faeces) can end ups suspended from trees / shrubs in woodland, or caught on wire fencing, waving n the wind. Discarded plastic items come in all shapes and sizes; those that are 5mm or smaller are termed “microplastics.” Microplastics come in part from larger plastic pieces that degrade into smaller pieces; but also from microbeads. Microbeads are very small pieces of polyethylene plastic that are added to health and beauty products, such as some skin cleansers and toothpastes. Now microplastics are to be found everywhere from deep oceans, to Arctic snow and Antarctic ice. They are found in foodstuffs and drinking water. One investigation found that if parents prepare baby formula by shaking it up in hot water inside a plastic bottle, their child might swallow tens of thousands of these microplastic particles each day. The movement of these particles through ecosystems is graphically summarised in this article. There is currently much discussion and research about how these microplastics will impact on the environment and different organisms, including us. Because they are so small and to be found widely in the environment, they enter organisms and food chains. Apart from the plastic in these particles, they may also contain chemical residues of plasticisers, drugs, and pharmaceuticals, and heavy metals may stick to them. Sometimes, sewage sludge may be used as fertiliser and this can contain nanoplastics. Also, treated wastewater is used for irrigation purposes and this again may be a source of plastic. Research indicates that earthworms in microplastic ‘enriched’ plant litter grow more slowly and have a shorter life span, and there is evidence that the gut of earthworms becomes inflamed after exposure to microplastics. Earthworms are important in aerating the soil and transporting materials such as dead leaves from the surface to deeper in the soil, they also 'inadvertently' transport micro-plastics. Springtails, a group of soil micro-arthropods (Collembola) can also help move micro-plastics in the soil. The movement of microplastics through the soil makes these materials ‘accessible’ to other soil dwellers but it is not clear if they pass along food chains (as has been the case with pesticides). Whether nano-plastics are taken up by or affect plants - again is not yet clear. However, the chemicals released by plastics such as phthalates may taken up by plants. There is a significant risk of physical and physiological damage to organisms and ecosystems by these micro-plastics *. The particles also get into the human body and the consequences for our health are, as yet, unknown. further information on nanoparticles etc : https://www.sciencedaily.com/releases/2022/04/220420133533.htm
April Fungi Focus – Chaetosphaerella phaeostroma
In my last post I wrote about inconspicuous ascomycetes – the kind of tiny species that hide in plain site, manifesting themselves as little black dots on dead plant matter such as woody stems. This time, I want to zero in on a species that is not quite so inconspicuous and which grows on dead deciduous wood. After spotting it for the first time this year, it then started popping up everywhere in my local woods and beyond. I’ve found it in three different sites over the past few weeks alone. And not only me, as I’ve seen numerous postings in various online mycological interest groups by people who’d stumbled across it just as perplexed as I initially was. Who knows, perhaps the conditions have been particular good for it this year, or perhaps it’s always been around and I’ve just never noticed it. It’s name is Chaetosphaerella phaeostroma, and though it doesn’t have a common name in English, I’d argue it probably should do, as it is a fairly distinctive species. From a distance, it manifests itself as black fuzzy patches. Up close however, one notices that nestling amongst the felty patches of hairs are dozens of tiny slightly rough textured dark bluey-grey to black spheres up to 0.5mm in diameter. [caption id="attachment_37861" align="aligncenter" width="650"] Chaetosphaerella phaeostroma[/caption] These are the perithecia of this pyrenomycetous ascomycetes – if you didn’t read last months post, these are the hard black spherical flasks that hold the asci sacs that in turn hold and release its spores of this particular group. Looking closely, you can see the top of many of them have broken away, like the tops of Easter eggs. There are many, many fungi species that consists of groups of tiny spherical perithecia like this (to name but a few, there are the various species in the genuses of Nischkia, Ruzenia and Rosellinia, if you care to Google them). But Chaetosphaerella phaeostroma is distinguishable from these due to the coarsely hairy mat its perithecia are immersed in, known as the ‘subiculum’ (defined as the net, felt, or crust-like growth that covers a substrate formed by a mat of hyphae from which fruiting bodies emerge). In fact, there was a time when scientists believe this was two separate species, the orb-like perithecia being one of them, the hairy subiculum being another. [caption id="attachment_37862" align="aligncenter" width="650"] The large distinctive spores of Chaetosphaerella phaeostroma.[/caption] Fungi are complex organisms that constantly seem intent on thwarting those whose attention they attract. So it’s perhaps no surprise to find out that there is actually another species, Acanthonitsckea tristis, that looks superficially much the same as Chaetosphaerella phaeostroma. Whether it is more or less prevalent in the UK, I don’t know, but as ever, the way to tell them apart is through microscopic examination of the spores – the fungi in focus has relatively large (20-25x6-9 microns) banana-shaped ones that are segmented into four with the end segments lighter than the middle two; Acanthonitsckea tristis has much smaller single-celled ones about 6-9x1.5-2 microns. [caption id="attachment_37863" align="aligncenter" width="650"] No hairy subiculum and totally different spores point towards an entirely different genus of Nitschkia for this otherwise very similar looking specimen.[/caption] I duly set about looking for the evidence, laying my find, after removing it from the wood with a penknife, facedown on a microscope slide overnight. The next day, I put the slide under the microscope and found thin curved ones, about 10x2 microns, which fit neither species. I was perplexed for a while, until the ever-helpful Emma Williams of the British Mycological Society pointed out that not only did the spores look more like those of the Common Tarcrust (Diatrype stigma), which I covered in some detail a few years back, or those of a number of other species in the related Eutypa genus, but that Chaetosphaerella phaeostroma doesn’t actually grow on dead deciduous wood, but parasitises these Diatrype and Eutypa species. I had stray spores. [caption id="attachment_37864" align="aligncenter" width="650"] In the top left of this picture you can see Chaetosphaerella phaeostroma growing as a parasite on its host in the bottom right, a member of the Eutypa genus.[/caption] And so I went back to break open the tiny perithecia and tried to ease a new batch of spores out. I was relieved that these did indeed perfectly match the large segmented spores of the Chaetosphaerella phaeostroma I thought I’d discovered. A closer inspection of the original photos also showed that beneath the margins of the felty subiculum, one could see the distinctive pimples of a Eutypa species upon which this was growing. Whereas the Common Tarcrust is fairly easy to identify, the various Eutypa species are not so much. Some grow as a crust with the perithecia embedded in a spreading hard black body (the stroma) on top of the wood, like the Common Tarcust, and some species grow with the stroma forming beneath the wood and the perithecia emerging through it as little black dots. Wikipedia notes this “widespread genus is estimated to contain 32 species”. Even my fairly specialist literature at hand notes only about four species in detail, and I found no records of which might be found in the UK. [caption id="attachment_37865" align="aligncenter" width="650"] This cross-section photo shows the perithecia of this Eutypa species growing beneath the surface of the wood.[/caption] To be fair, such widespread but generally unremarkable types as Eutypa, of which we can find many more examples within the vast understudied field of ascomycetes, are not likely to be of much interest to anyone beyond those who have dedicated their life to the study of such things right down to the level of molecular genetics. I quickly decided it wasn’t worth my losing much sleep over narrowing it down to a species level. However, that they themselves play host to more interesting species like our focus species, Chaetosphaerella phaeostroma, and therefore provide vital clues as to their identification, is more of interest to the amateur mycologist, and points to the complex and little understood interconnectedness of our woodland ecosystems. (I have covered several such examples of fungi-on-fungi relationships previously in these postings, including the Yellow Brain, the Silky Piggyback and the Bolete Eater). The other purpose of this month’s post is also to remind ourselves how surface features of many fungi only get us so far, and that how the complex and unusually-shaped spores of many of the otherwise nondescript ascomycetes can be a handy guiding feature. [caption id="attachment_37866" align="aligncenter" width="650"] The lack of the fuzzy subiculum, the vestiges of white downy hair on the perithecia and in particular the long, worm-like spores guide us to an identification of Woolly Woodwart.[/caption] As an example, I just want to quickly mention another species I found recently beneath a damp, well-rotted deciduous log, the Woolly Woodwart (Lasiosphaeria ovina). The one has an english name, and one that reflects its appearance. While it too grows as tiny spherical perithecia that match the size of those of Chaetosphaerella phaeostroma, these are not immersed in the same black felty subiculum but are typically covered in the woolly white hairs that give it its common name. Except, however, that in the case of the specimen I found, these hairs had worn away, leaving distinctly un-woolly little black balls with little to identify them from without diving into the microscopic realm. Fortunately this was another one with highly unusual looking spores; large, long and worm-like, with dimensions around 40x5 microns, and singled celled – indeed, I initially thought I’d chanced upon a stray nematode on the microscope slide. There are dozens of pages of tiny non-stromatic pyrenometous species listed in my go-to guide Fungi of Temperate Europe (vol 2., to be precise), and many many more unlisted. I hope that the example of Chaetosphaerella phaeostroma shows that not all need a microscope for identification, and that its not worth being too daunted by this group. [caption id="attachment_37867" align="aligncenter" width="650"] Chaetosphaerella phaeostroma[/caption]
Of owls and dormice
Dave and I bought our lovely wood in Kent in 2019 because we wanted to surround ourselves in nature and have somewhere our children could visit to decompress from their busy lives. In due course, we hope our as-yet-unborn grandchildren can come and explore amongst the trees to root them firmly in the natural world. One day, we wish them to become the custodians of this beautiful space. But it was more than that for us. Dismayed by on-going news of threatened wild spaces, we wanted to play our small part to protect, cherish and encourage the biodiversity that calls our wood its home. Understanding how the wood ticks throughout the year was a steep learning curve for us and one that we shall still be climbing for many years to come. We have dug several small ponds, put up bird feeders and a large number of bird boxes, as well as clearing some glades and coppicing the hazel through the winter. Trail cameras have been sprinkled liberally around, all the better to find out what the wildlife is up to when we are away. We have found that there is a thriving population of Hazel Dormice in our wood and there are several badger holes and fox dens. [caption id="attachment_37873" align="aligncenter" width="640"] A Hazel Dormouse that has made a nest in a bird box[/caption] Green Woodpecker nest in the same hole in a cherry tree every year and this spring we have the thrill of a pair of Tawny Owls setting up home in one of our owl boxes. [caption id="attachment_37874" align="aligncenter" width="623"] A Tawny Owl hunting for worms on the woodland floor[/caption] White Admiral and Silver-washed Fritillary butterflies glide majestically through the woodland glades in August and Woodcock and Redwing fly in from distant lands to spend their winters here with us. We feel that the wood has given us so much - the joy of a deeper understanding of the woodland habitat, a space to clear our heads, bountiful aerobic exercise, and, in a small way, the opportunity to give a little bit back to the world.
Tree Planting Spades
So, you’ve decided to plant some trees and are wondering what tools you’ll need for the job. Whether you’re planting a select group of ornamental species, a bountiful orchard of fruit and nut trees or a new broadleaved woodland, there is one key aide which will take you a long way – the humble tree planting spade. This is a short guide to what you might find on the market and the differences between various spades. Spade or Spear? Most tree planting tools will fall into one of two categories: Spades - those shaped like a traditional spade with a curved head and a flat cutting edge at the bottom. They will look similar to a normal garden spade but much smaller. Spears – those with a flat face and a point at the end, designed to create a slot in the ground when pressure is applied to the tread by foot. Spades can be used to dig holes for planting and move soil around, making them more versatile tools, whilst spears are excellent for planting cell-grown* or bare root* stock, but are somewhat limited to this sole function. If planting larger trees with established root systems (root-ball* trees), then a spade is definitely the tool for you, as the slot created by a spear would not be sufficient to house the root system without causing crushing. In contrast, for those looking for an efficient method to plant lots of small trees quickly, for example when establishing new woodland for carbon offsetting purposes, then a spear should definitely be considered. Comfort is key Like many things, it often comes down to personal preference and what you feel most comfortable with. There is no right or wrong tool to use, as long as the tree is planted in a way that does not damage it (for example by burying the root collar) then you’re on the right track. Planting trees is a wonderful thing to do and as much as possible, you should work with tools that make the process a pleasure, which hopefully means you’ll spend more time doing it! Other factors to consider An often-overlooked detail is the length of the shaft and handle, which for those who are slightly taller or have the odd back pain, can make a big difference! A nice long handle will take the strain off those sensitive back muscles, as well as offering a bit more leverage which can be of assistance when planting in heavier soil types. The materials and quality of construction is also important; try wherever budget allows to buy once and buy well! Some cheaper tools made from inferior parts may not stand the test of time, or worse still let you down when you’re out in the field with a bag full of whips. A solid wooden handle (or better still stainless steel) with a galvanised steel head is a good option, ideally with a double-riveted socket which will provide greater strength. Where to buy and how much? Tree planting spades are available to buy at most garden centres and agricultural supply stores, such as Mole Valley. They are also widely available to buy online from specialist tool suppliers. Whilst you could pick one up from as little as £20, and pay up to £100 for the very best, you will be able to buy an excellent spade for around £30-£35. Bulldog Tools are a reliable supplier and would be a good option to consider. Do what works for you! Planting trees is good fun and of benefit to the planter, the wider community and the environment. A communal activity and a great form of exercise, the more trees we can all plant, the better! This means that you should use a planting spade (or spear) which is comfortable to use and gets the job done. If possible, try out a couple of different designs and manufacturers (borrow from a friend or neighbour where possible) before making the decision, but always remember they are in essence doing the same thing – making a home for a tree where it will live for many years to come. *Tree types Bare root trees – Produced by sowing seeds into outdoor beds. During development, seedlings are undercut to encourage a healthy root system. When ready, the trees are lifted and shaken by a machine to remove the soil, revealing the ‘bare’ roots of the tree. They can only be lifted and planted during the winter months when they are in a state of dormancy. A cost-effective option. Cell grown stock – These trees are developed in a compost ‘cell’ or ‘plug’ and can be seen as an intermediate option between bare root and pot grown. When removed from the cell, the fibrous root system is contained with the compost which remains on the roots. More expensive than bare root but generally has a higher success rate and can be planted all year round. Root ball or pot grown – These trees are the most developed and largest of the three options and are delivered with a significant ball of soil surrounding an advanced root system. The root ball will be encased in a biodegradable material. Great for those who want more established trees from the offset, although there is a price to be paid for this benefit.
Woodlands web update 15.
Lichens losing ? Sitting on the bark of many trees and on the surfaces of fences and walls, there will be lichens. They are there in summer, winter, spring and autumn. Lichens come in an amazing variety of shapes, sizes and colours. Some can grow in extreme environments such as the rocky summits of mountains. Such lichens grow slowly and may live for hundreds of years. Lichens are rather unusual in that they are an amalgam of two (or occasionally three) organisms : a fungus and algae. They are symbiotic systems, where the partners of the association work together for mutual benefit. The fungus makes up the bulk of the lichen’s structure (known as the thallus), but the algae (green algae or cyanobacteria) are essential as they can photosynthesise and provide the organism with carbohydrates. Lichen covered tree One of the most common algae found in lichens is a species known as Trebouxia. It can exist in association with a fungus to form a lichen, or as a free living organism. If the Earth’s warming continues at the present rate, it may well be too hot for certain species of Trebouxia to survive (in their normal range). Dr M Nelson of the Field Museum (Chicago) has looked at the adaptability of Trebouxia species and suggests that it could take hundreds or thousands of years for Trebouxia species to cope with the temperature changes that we are currently experiencing. These algae may well lose out in the evolutionary race to cope with climate change. This would, in turn, affect many different species of lichen. Lichens are important in arctic tundra ecosystems, where they together with mosses and liverworts make up the majority of the ground flora. They contribute to food chains, for example, reindeer moss is not a moss but a lichen. Lichens are also pioneer species - they can colonise bare rock and contribute to its weathering (their exudates chemically degrade and physically disrupt the minerals). Lichens may be used by birds as nesting material. Hedgehogs. Rural hedgehog populations are still in decline, dropping by 30 to 75%, this is in contrast to urban populations that are ‘steady’. Though urban populations suffer mortalities on the roads, well managed urban areas, parks and wildlife-friendly gardens provide refuges for hedgehogs. The loss of hedgerows and diminishing field margins is contributing to the decline of rural populations. Land of Plenty report The WWF-UK has produced a report entitled “Land of Plenty”, which addresses some of the problems that the UK faces now and in the coming decades. There are many reports relating to the loss of plant and animal species and the degradation of particular ecosystems (flower-rich meadows, peatlands, salt marshes etc). Sadly, much of this damage has been associated with the expansion of our farming / food production systems; indeed some 70% of the land is involved in agriculture. The WWF report outlines how a move towards regenerative farming / agriculture can significantly reduce CO2 and methane emissions, reduce pollution (from fertilisers) and help with biodiversity and resilience. Such changes would (in time) help limit farmers’ exposure to extreme weather events that affect crops / harvests. One of the many suggestions in the report is the expansion of ‘woodland creation programmes, focussing on potential for broadleaf and native species’. The focus would be on natural regeneration in the first instance, but supported by active tree planting. Full details of the report available in PDF format here. Drought, bark Beetles and fires. Woodland recovering from a fire The Cameron Peak Fire in the Rocky Mountains of Colorado and the Creek Fire in the Sierra Nevada of California burned through forests where large number of the trees had been killed by bark beetles. Warmth favours the bark beetles. Mountain pine beetles had killed millions of lodgepole pines. A dead tree does not take up water, it dries out. The drying out was ‘helped’ by the drought that the West Coast has experienced in recent years. The fires burned with incredible ferocity. In the case of the Creek Fire, the plume reached some 50,000 feet up into the air. The fires were the result of Drought / climate change Bark beetle infestation Large numbers of dead, dry trees Consequently, large amounts of energy-rich dry biomass Full details of the factors behind the forest fires here. Drought is a major ‘stressor’ affecting many ecosystem across the globe. To understand how drought affects different ecosystems, DroughtNet is working with a number of existing projects and the International Drought Experiment (IDE). A recent experiment at the University of Florida demonstrated how drought-stressed pines did not grow as well, and when faced with an invasive species and fire - they were much likely to succumb than a healthy tree.