The woodlands blog has previously reported on the danger that the Tree of Heaven presents. Whilst its foliage and fruits are attractive, it can be a highly invasive plant. it can overwhelm natural vegetation / species because
- It grows extremely rapidly
- It can produces thousands and thousands of seeds in any given year
- It can spread by underground suckers
- It produces chemicals that inhibit the germination and growth of other species - a phenomenon known as allelopathy.
Hawkweeds are wild flowers of dry, grassy places, but also to be found on walls, rocky places, and pavements. Some are regarded as invasive species in some parts of the world. The botanical genus Hieracium is known by the common name : the hawkweeds. It is thought that the common name derives from the writings of Pliny the elder, who believed that hawks sprinkled sap from the plants into their yellow eyes to dispel dimness.
The genus is a member of the sunflower / daisy family: the Asteraceae. They are closely related to dandelions (Taraxacum) and sow thistles (Sonchus). There are thousands of different Hawkweeds; but botanists classify British hawkweeds into about 340 “species”, many of which are quite rare. Identifying them is difficult and best attempted when there is fresh growth and new leaves. The classification of the hawkweeds is difficult, partly because the plants use apomictic reproduction. This means that seeds that are formed without the usual processes of pollination and fertilisation. Read more...
It seems that the UK is losing the battle to eradicate the giant hogweed. It is an invasive species which has been described as the country’s most dangerous plant. Many efforts have been made to eradicate this plant. Local authorities can make use the Wildlife and Countryside Act 1981 and The Anti-social Behaviour, Crime and Policing Act 2014 to enforce control of the weed. Sadly though Plant Tracker has recorded hundreds of sightings across the four nations of the U.K.
Its scientific name is Heracleum mantegazzianum and it belongs to the same family as the wild parsnip, the Apiaceae. It is sometimes referred to as the giant cow parsnip, the giant cow parsley or the cartwheel flower. Read more...
Nearly every report that one comes across says that many plant and animal species are under threat. The causes are many but may be broadly summarised as
- Fragmentation, loss or destruction of natural habitats (as a result of intensive and extending agriculture, roadways, railways etc)
- Pesticides and pollution (e.g. neonicotinoids, eutrophication as a result of fertiliser use)
- Impacts of climate change
Some of the changes are more obvious in every day terms than others, for example, the drop in insect numbers is revealed by the car windscreen ‘test’ : the splatometer. A survey of insects hitting car windscreens in rural parts of Denmark [using data collected between 1997 to 2017] found a decline of some 80%. There was a similar decline in the number of swallows and martins, (they depend on insects for their food). Read more...
Atlantic oak woodland is often referred to as the Celtic Rainforest. It is characterised by lichen covered trees, together with a rich moss and liverwort flora. The environment is damp and humid, with streams and waterfalls contributing to this. These woodlands have evolved under the influence of the Gulf Stream, which helps keeps the area warm (and wet).
The difficult access and rugged terrain (in some areas) has helped to preserve these woodlands, plus they have not proved suitable for agriculture or ‘industrial forestry’. Consequently, in many areas, they have remained in their 'ancient state', going back to the last ice age. Their sessile oaks are very important for wildlife but as they are not always productive of good timber, they have often been left to grow to maturity. By the same token, Birch trees have relatively low timber value - which has been their salvation. Woodlands like this were more extensive in the past covering the Atlantic fringe of Western Europe from North West Scotland down to the South of Portugal. This type of woodland is rich in terms of biodiversity (primroses, violets, wild garlic, ferns and grasses) and some species are only to be found here and nowhere else in the world. Read more...
Mesquite is the name given to a number of leguminous shrubs or trees that belong to the genus Prosopis. Many of these plants are native to southern parts of the United States and Mexico, though one species is native to South America - Argentina. Generally, they are plants of very dry (arid or xeric) regions. They have the capacity to form very long, deep roots that seek water deep underground.
The trees / shrubs are deciduous and their leaves are pinnate (a compound form of leaf); they are also thorny. The trees produce flowers through Spring and Summer, and the seeds (beans) form in pods. The trees can be used as a source of timber (for furniture, and in the past ship building). Read more...
Recently, the IUCN (International Union for the Conservation of Nature) carried out a survey of the state of trees through Europe, specifically related to their risk of extinction. There are some four hundred native tree species spread across Europe.
Trees are not just essential for life on Earth (generating oxygen through photosynthesis) but they also provide food and habitats for hundreds of species - birds, mammals, insects, spiders etc. The loss of tree species has considerable ‘knock on’ effects in terms of the biodiversity of an area. Trees also provide us with timber and other materials (cork, cellulose, oils). Read more...
Globalisation is the process by which economies and cultures are drawn together; they become more inter-connected through the flow of trade, capital, people and technology. This has occurred in part due to the rapid growth of air travel, container shipping etc. so that there are now massive movements of people and goods (both raw and manufactured). One positive aspect of globalisation is that we have access to foods and materials from all over the world. A downside is that disease, parasites and pests can ‘hitch a ride’ with people or materials and goods as they move across the world. Plants and animals can also change their geographical range / distribution as a result of climate change. The woodlands blog has outlined some of the problems associated with various ‘alien or invasive’ species, for example,