A forest is a place where thousands of different
organisms meet, creating the most complex
network of connections that can exist in nature. Forest ecosystems
are also huge factories where solar energy and carbon
dioxide from the atmosphere are turned into a huge
amount of biomass, which makes up ecosystems, but is also constantly changing. A forest is a system in which
each organism plays a role and has an assigned function. It is worth considering
the importance of fungi for the functioning
of the forest, the most mysterious group of organisms in
this forest puzzle. LIFE OF THE FOREST.
Fungi. Fungi, that is representatives
of one of the five kingdoms of the world of
living organisms, play an extremely important, often unnoticeable
or underestimated role in the functioning
of all ecosystems, including forest ecosystems. It is also one of the
richest groups of organisms in terms of species
all around the globe. It is estimated, that there may even
be over 5 million species of fungi on our planet. A walk in the woods,
especially in the fall, can be an opportunity
to get to know the amazing variety
of fruiting bodies that fungi produce. Our attention is
especially drawn to the so-called larger fungi, otherwise known as macrofungi. Their fruiting bodies can
be seen with the naked eye. Mushrooms are undoubtedly
the most famous fungi. Their fruiting bodies vary
greatly in size and colour. The size of some of them does not exceed one centimetre, but we can also find those with caps that extend
over 20 centimetres. It is also worth
paying attention to the huge variety of
fruiting body colours, which depends on the species. On our path we can
come across mushrooms with caps ranging from
white, through yellow, green, olive, pink, red,
brown and to dark brown. However, mushrooms are not
the only fungi found in the forest. An attentive observer
will also find fungi with different fruiting bodies, often surprising in form, which can be cup-shaped, bush, spherical, bulbous, pear-shaped, star-shaped
or funnel-shaped. Most fungi, colloquially
known as bracket fungi, produce fruiting bodies
resembling tongues, consoles or hooves. The fruiting bodies are made
with basically one purpose to produce huge
amounts of spores, which is one of the primary
ways for fungi to spread. When observing fruiting bodies, it is also worth
paying attention to the variety of forms
of the hymenophore, that is the layer in which
spores are produced. The species that predominate among the fungi have tubular or lamellar hymenophore. However, we can also meet species with
a more unusual hymenophore, that is spiny,
labyrinthine or smooth. Contrary to appearances, fungi form fruiting bodies
almost all year round. For example, velvet
shanks appear in September and are found until April, usually in frost-free periods. Fruiting bodies of velvet shanks usually grow near
stumps of deciduous trees They are saprophytes, and therefore decompose
dead organic matter A similar method of
obtaining carbon compounds can be observed in many fungi. In early spring, fruiting bodies of
common morels appear, fungi that are currently
under partial protection, or of equally rare false morels. In the summer season, we can often find fruiting
bodies with unusual colour. Caps of verdigris agaric are turquoise in colour and they often sprout
up from rotting logs, usually in older forests. Their shimmering caps are a real decoration
of the surroundings. As a rule, saprotrophic fungi have their own food preferences. A significant part of them is related to dead wood. The fruiting bodies, commonly called bracket fungi, are observed in every forest. Many arboreal fungi are particularly
rare and protected species. Due to their presence, arboreal fungi gradually
break down the wood. Ecological niches useful for
other species appear over time. Due to this specific succession, huge trees often get a
second life after their death, during which hard and
compact matter turns into dust in a long-time process. Whether fungi break down organic matter from the soil
or live on dead wood, they play a key role in the circulation of
elements and energy in nature. The efficiency of
fungal decomposition is best seen when observing
the decomposition of forest litter, in which, among
many organisms, fungi, both larger and
microscopic ones, play a leading role. Another way for fungi to gain nutrients is to live at the expense
of other organisms. The pathogenic fungi in question attack
many organisms, including plants. In natural forests, pathogenic organisms are a
natural component of ecosystems in which they play
an important role and are regulators
of other organisms. This is not the case for forests
that have been heavily influenced by humans over the last decades. The maladjustment of
the species composition to the habitat and the
simplification of the spatial and age structure make such forests
particularly sensitive to the presence of
fungal pathogens. An example is the
massive dieback of oaks. The process that affects
these majestic trees since the 1980s is caused
by fungus-like oomycetes, leading to the
so-called phytophthora. In the first stage
of oak dieback, the infection of
the roots begins, followed by further
damage to the trees, related to the attack of insects
feeding in the crowns and wood. The spiral of death into which single
trees are woven causes changes in the entire
forest ecosystem, which are most visible in
changes in the species composition of undergrowth plants. Currently, next to oaks, the most endangered
trees are ash trees, attacked by the fungus Hymenoscyphus fraxinea, discovered at the
beginning of the 21st century. This pathogen creates small
fruiting bodies on ash shoots. While old trees
resist the attack, it basically completely
eliminates young ash trees that are regenerating
themselves. Elms are another
threatened tree. The first reports of a
massive dieback of elms appeared at the beginning
of the 20th century. During this time, 10–40% of all elms
growing in Europe and North America were affected. Later, a new species of
fungus was described Ophiostoma novo-ulmi, which caused an almost
complete extinction of the mountain elm in southern
England in several years. Small insects, large elm bark beetles, which are the only vector that transfers the
fungus to new areas, contribute to the spread
of Ophiostoma fungi. Mycorrhizal fungi are an extremely
interesting group of fungi, without which it is
difficult to imagine the functioning of
terrestrial ecosystems, including forests
in the present form. Throughout their life, they remain in a close symbiotic relationship with plant roots, creating mycorrhiza. Mycorrhiza is not a
homogeneous phenomenon/system. Its division into different
types is most often related to the systematic position
of the plant partner. Heather plants,
represented in forests, for instance by
blueberries and heathers, form the so-called
ericoid mycorrhiza. A separate type of mycorrhiza is also created by
orchids whose flowers please our eyes
during forest walks. The most common type of
mycorrhiza in terrestrial ecosystems is the arbuscular mycorrhiza. It occurs in most herbaceous plants, including forest ones. Also some shrubs,
such as buckthorn, bird cherry, as well
as some forest trees, such as maple and ash, are characterized
by the presence of arbuscular mycorrhiza. However, the most important
type of mycorrhiza in the forests of
our climate zone is ectomycorrhiza. It applies to most
of our forest trees, such as pines,
spruces, larches, oaks, beeches, lindens,
birches and hornbeams. When in contact with the mycelium of ectomycorrhizal fungi, the fine roots of these
trees lose their hairs, fundamentally change
their morphology, undergo numerous branches, and their surface is
covered with fungal hyphae. The mycelium forms the
so-called mycelial muff, the structure and colour of which
depend on the fungus species. Thanks to this, this underground
world of ectomycorrhizae does not differ in diversity from the variety
of fruiting bodies. Most edible species are found among the fungi
that form ectomycorrhiza with forest trees. These include larch boletes, bay boletes,
boletus, chanterelles, edible milkcaps or russules. Inedible and poisonous fungi, which are ectomycorrhizal, include for instance toadstools. Mycorrhizal fungi, unlike saprotrophic fungi, have lost the ability
to decompose and use dead organic matter
as a carbon source. In this respect, they depend entirely
on their plant partner to donate to them some
of the carbohydrates produced by photosynthesis. In return, fungi, thanks to the extensive
mycelial network extending over the substrate, provide plants with increased
access to water and minerals. Additionally, they are an element of
protection of the plant partner against soil pathogens. The ectomycorrhizal
fungal hyphae spreading over considerable
distances in the soil form the so-called common
mycorrhizal network. It connects the roots of trees, even those belonging
to different species, so that one common
"super organism" is created. The purpose of this
network is also to support the growth of seedlings
under the canopy of adult trees. Autumn is the time when we especially
like going to the forest. Most often it is not only due to our willingness to
commune with nature. The aim of these trips
is mushroom picking, which can be safely called the national sport of Poles. Mushroom picking has a centuries-old
tradition in our culture. Undoubtedly, many of us remember the very pictorial description
of mushroom picking, which was included
in the third book of "Pan Tadeusz"
by Adam Mickiewicz, Poland's national bard. In September and October, when the weather is favourable for fungi, forest parking lots
and roadsides fill up. In many regions of Poland, you can then meet
dozens or even hundreds of people setting out
on mushroom hunting. Most often, they collect some
of the most known species, such as larch
boletes, bay boletes, boletus and birch boletes. Most of the collected mushrooms are intended for personal use. Some mushroom pickers, however, treat autumn trips to
the forest as a source of additional income. We can buy fresh mushrooms
on the sides of roads running through forests, at city markets and more and more often
in large supermarkets. The trade also includes
dried mushrooms, in various pickles, or constituting an
ingredient of various dishes, for instance dumplings or pates. The Polish law allows for the marketing and
processing of 44 species of fungi, most of which are
forest mushrooms. Despite media
reports of poisoning, unfortunately often fatal, caused by the consumption
of poisonous fungus, such cases are
repeated every year. One of the most dangerous
"mushroom killers" is undoubtedly the
amanita phalloides, commonly known as the death cap. It is most often confused
with the edible russule, yellow knight or
parasol mushroom. In today's changing world, the priority is the
protection of nature and the protection
of biodiversity. The best way to protect fungi is to take special care
of their natural habitats. Since we find the
greatest species richness of fungi
in forests, therefore, by protecting the
most valuable forests, we also protect the world
of fungi occurring in them. It is often a world
of incredibly rare and endangered species. This is the case, for example, in the forests of the
Białowieża Primeval Forest, which is the best-studied
forest complex in Poland in terms of the
fungi found there. The dizzying amount
of micro-habitats associated with a huge
amount of dead wood of varying degrees
of decomposition, but also the diversity
of these habitats makes it an ideal place
for fungi conservation. However, the vast majority
of forests in Poland are managed forests. In such forests, fungi can be used as
indicator organisms, useful for observing
the impact of changes in forest ecosystems
due to human activity. The managed forest is
a place where various, often contradictory
expectations and goals meet. In addition to
protective functions, the forest also performs
economic functions related to the
production of wood. The biggest paradox with wood, the most natural, renewable and fully biodegradable
raw material is that perennial trees must
be cut down to produce it. On the one hand, wood is a raw material without which it is difficult
to imagine our life. On the other hand, the sight of trees being
cut down and felled often causes
indignation and anger. However, the life of the forest goes on. In order to reduce the negative effects of human interference, it is important to
ensure the fastest possible regeneration
of the ecosystem, preferably with the use
of natural processes. The best example of this is the promotion of
natural regeneration, thanks to which the forest
regenerates very quickly. Leaving the felling
remnants also allows you to find ecological niches
suitable for various fungi. The spread fruiting bodies
of the Tomentella genus are a great peculiarity
of deciduous forests. The appearance
of fungi in the forest, first the common ones, with time other, rarer ones, proves how quickly the forest is able to heal wounds. In this way, the young generation
of the forest takes care of its fungi, and they support the newly created forest. The use of natural processes is not always possible
to the same extent. Poor pine forests are
a common landscape feature in many
parts of the country. Contrary to appearances, such forests are quite
rich in fungi found in them, from porcinos,
chanterelles or bay boletes, to less known russules, milk-caps and webcaps. To ensure the
persistence of fungi, it is necessary to
restore the forest as quickly as possible. It is very important
to introduce other tree species
wherever possible. Each newly
introduced tree species, which will diversify the species
composition of the forest, will in the future create a
niche for the occurrence of hundreds of fungal
species associated with it. Most of the planting
material used in artificial forest regeneration is produced in field nurseries. All our forest trees
are obligatorily mycorrhizal species, which means that they
are not able to grow properly without being associated
with mycorrhizal fungi. Hence, it is extremely important that tree seedlings
produced in nurseries are characterized not only by the correct
growth parameters, but also by a high
degree of colonization by mycorrhizal fungi diversified in terms of species. This is an element
that undoubtedly influences the
high efficiency of planting and afforestation. Many years of research conducted at the Institute of Dendrology of the Polish Academy
of Sciences in Kórnik have proven that
in this respect, the Polish forest nursery can be a model to follow. The world today
brings many dangers to the diversity
of the fungi world. One of them is
the overexploitation of forest resources, for example a shift
away from the model of sustainable forest management to plantation crops. Improper actions
in managed forests can permanently change
the nature of forests by simplifying their structure and species composition, which will also have
a negative impact on the world of fungi. The serious consequences
of errors in forest management can be observed today
in many single-species stands established at the
beginning of the 20th century. The maladjustment of the species composition to the habitat, the use of seeds
from unknown origins and the focus on rapid growth make such forests more
vulnerable to threats. The changing climate, more frequent and longer
droughts and frost-free winters result in massive
outbreaks of xylophagous insects and fungal pathogens. The changing climate
means also more and more frequent extreme
weather phenomena, such as storms,
tornadoes and heavy rains. The cascade of events
triggered at the moment of the forest's death also affects the world of fungi. Mass forest dieback
is the greatest threat to the diversity of fungi, especially the symbiotic fungi associated with living trees. This is a loss of habitat for thousands of species of
fungi associated with forests. That is why the fight
for the sustainability of the forest is so important. For each piece of the forest that resisted the unfavourable, currently observed changes. Among our native fungi, there are more and more
newcomers from far away. Foreign species often make impression
with their colours and shapes. Octopus stinkhorn occurs naturally in Australia
and New Zealand. It came to Europe at the
beginning of the 20th century, probably along
with imported goods. In recent years, it has become quite
common in Poland. The octopus stinkhorn’s spores are spread by flies attracted by the smell of perishable meat. Another newcomer
from distant lands is a matte Jack. It came to Europe
from North America along with Douglas fir. This duo has also been dragged to other parts of the world. In the southern hemisphere, especially in South
America and New Zealand, a matte Jack is
a decisive factor in the invasiveness
of Douglas fir, which is a great threat
to native tree species. From North America
we have also received an Aureoboletus projectellus. For several years, it has been more and more often found in the dry pine forests of the coastal belt. This mushroom is known in Poland as a
„heather boletus”. Its characteristic
feature is a grooved stem, not found in our
native mushrooms. Aureoboletus projectellus has been harvested by
mushroom pickers for several years. At the end of August
and September, they appear en masse, creating thousands
of fruiting bodies, and this attracts mushroom
picking enthusiasts from many parts of Poland. „Heather boletus” has
become a tourist attraction of coastal forests. However, it should be remembered that this is a species
of foreign origin, the impact of which on
our native ecosystems and species of fungi has not yet been understood. Mass collections of
Aureoboletus projectellus meant that it was moved to the interior of the country. The vector that contributes
most to the spread of this fungus to
new areas is a man. When wandering through forests, we should remember that
a forest is not only trees, bushes and undergrowth plants. It is a very complex system in which different groups
of organisms coexist. Among them, fungi play an important role. Remember that the
fruiting bodies of fungi are an important element
of a number of food chains. They are food for many rodents, snails or insects. Therefore, mindless destroying
of the fruiting bodies should be avoided. The fact that they are
not culinary attractive to us does not mean that
they are redundant. Through a number
of different functions, fungi ensure the sustainability and proper functioning
of the forest ecosystem. It is hard to imagine the sudden
disappearance of the fungi and the consequences
it would have.
