Month: Mar 2020

Birch trees adjust their stem thickness to support their weight.

Trees are known for their great, but not unlimited, trunk height and diameter. They have evolved to develop a heavy above-ground biomass, but this integral feature poses a challenge to the trunk’s stability. Despite its evident importance, the principle by which plant stems respond to their increasing weight remains unknown. To address this question, a theory of “vertical proprioception”, a mechanism that balances the radial growth of the stem with the weight increase, has been developed.

To study the theory, researchers at the University of Helsinki, University of Cambridge and Natural Resources Institute Finland manipulated the aerial weight of downy birch (Betula pubescens). The authors observed that the tree was indeed able to adjust its stem radial growth in response to the added weight, and the strength of this response varied along the length of the stem. Furthermore, a degree of lateral stem movement was required for this response: static trees did not grow as thick as free-moving ones.

“Even though the idea of plants sensing their own weight and thickening their stem accordingly sounds intuitive, our study is the first one to address this question in trees”, says Juan Alonso-Serra from the Faculty of Biological and Environmental Sciences.

One approach to understand how this weight-sensing mechanism works is by comparing normal plants with plants lacking this ability. The researchers took advantage of a naturally occurring birch mutant named elimäki. This exceptional tree grows upright for three months, after which its stem suddenly bends at the very base, and the whole tree collapses.

The researchers showed that, unlike normal trees, elimäki trees fail to properly adjust their width to their increasing weight, which makes them less stable mechanically. According to the researchers, the lack of a proper response in elimäki trees is linked to a single position (locus) in the birch genome, enabling the future identification of the mutated gene.

Birch is an ex­cel­lent model tree

The use of mutant trees was a key part of the project. In most plant models, such as Arabidopsis, genetic studies are feasible because a new generation can be produced within months, whereas the same typically takes decades with trees.

However, birches are exceptional as they are the among the few tree species where flowering can be induced already at six months’ age. This provides a unique opportunity to address basic and applied questions concerning the life and development of trees.

More information: Alonso Serra, J. A et al. (Accepted/In press). ELIMÄKI locus is required for vertical proprioceptive response in birch trees. Current Biology.
Jan 20 2020.

🍀”And the people stayed home. And read books, and listened, and rested, and exercised, and made art, and played games, and grew gardens full of fresh food, and learned new ways of being, and were still. And listened more deeply. Some meditated, some prayed, some danced. Some met their shadows. And the people began to think differently.

And the people healed. And, in the absence of people living in ignorant, dangerous, mindless, and heartless ways, the earth began to heal.

“And when the danger passed, and the people joined together again, they grieved their losses, and made new choices, and dreamed new images, and created new ways to live and heal the earth fully, as they had been healed.”🍀

~Kitty O’Meara 1839 – 1888
Irish-French Catholic Author

This is a time to console, not to condemn.
This is a time for grace, not criticism. This is a time to sing, not to curse. This is a time to heal, not to anger. This is a time for love, not to hate.
This is a time to be kind, not to be mean. This is a time to be generous, not to hoard. This is a time for warmth, not to be cold. This is a time to be the change, not to stay the course. This is a time for deep rest, not for heavy stress. This is a time to come together, not withdraw. This is a time to give thanks, not to dread. We are the stewards of an abundant Creation, no more weary fools of illusory separation.

I’m here with you and for you. Let go. Allow. Embrace the shift. Together we stand.

Because I love you so much ~ Sean J Kennedy.

HAPPY SPRING EQUINOX!

The beauty of the trees,
the softness of the air,
the fragrance of the grass,
speaks to me.

The summit of the mountain,
the thunder of the sky,
the rhythm of the sea,
speaks to me.

The faintness of the stars,
the freshness of the morning,
the dew drop on the flower,
speaks to me.

The strength of fire,
the taste of salmon,
the trail of the sun,
and the life that never goes away,
They speak to me.

And my heart soars.

-Chief Dan George

As birds busy themselves with rearing young, we take a look at 8 birds and consider how they construct their nests.

A century ago, it would have been difficult to find a country lad who didn’t know the difference between a song thrush’s nest and that of a blackbird or who couldn’t tell you where best to look to find a clutch of sky-blue hedge-sparrow eggs.Here we reveal how to identify bird nests:

Blackbird
Hen blackbirds, rather than the cocks, usually choose the location for their nest and, although trees or bushes are the favourites, nests in sheds or buildings are not unusual. Among the more bizarre sites recorded are the engine of a parked aircraft and even a tractor in constant use. One nest was found 100ft high in an Edinburgh sycamore.The nest itself is a substantial cup, typically made from dry grasses, roots, stalks, moss and mud, but it’s not unusual for sweet papers or pieces of string to be included. The cup itself is lined with dry grasses. If you watch a hen blackbird building her nest, you’ll find she shapes it with her breast, pulling loose grasses down towards her.

Wren
When it comes to enthusiasm for nest building, few birds can rival the cock wren. Every spring, he builds a number of neat, domed nests, each one made of moss, dry grass and dead leaves, sometimes with a little bracken. These are generally known as false or cock nests, for the hen will eventually select the one she likes and she takes sole responsibility for lining the nest chamber with feathers, resisting any offers of help from her mate.
The wren may use the same nest for repeat broods, although it may well be employed again in the winter for roosting. Because of their small size, wrens struggle to maintain body heat during a winter night and often roost communally.

Osprey
Few birds are as site-faithful as ospreys—established pairs almost always return to their old nest, year after year. The nests themselves are often huge, the result of decades of annual additions. At the peak of nest-building, a pair may make more than 100 trips a day, bringing in sticks and branches. As egg-laying approaches, the birds will bring softer materials, such as grasses or even seaweed, to line the nest. Typically, osprey eyries are located in exposed sites where they’re subject to gale-force winds, so their stability depends on their size and weight. Although a typical Scottish osprey eyrie will be on a large, flat-topped pine tree, these birds are quick to adopt nesting platforms provided for them.

Reed Warbler
In recent years, we’ve unravelled numerous mysteries of the bird world, such as the migration route of the cuckoo (revealed by satellite tagging). However, many still remain, such as how the cock reed warbler manages to wind the very first blade of grass around the three to five reed stems that will eventually support his woven nest.
A finished reed-warbler nest is a beautifully woven basket of long, dried grasses, lined with hairs or similarly fine materials. It’s a deep and comfortable cup and, here, the clutch of four or five eggs will be laid. Many cuckoos start their life in reed-warbler nests, as the reed warbler is a favoured host.

Song Thrush
In size and construction, even choice of site, the nest of the song thrush is much like that of the blackbird. There is, however, one major difference. The song thrush invariably includes a smooth lining, made from a mixture of mud, clay, cow dung (if available) and rotten wood, mixed with saliva, forming a hard, cork-like base. Building such a nest is a lengthy business: most of the work falls to the female, although sometimes with a little help from her mate.
The first nest of the year may take two weeks or more to build, but those made later in the season are often put together much more quickly, with a corresponding loss in quality. However, song thrushes will reuse the original nest for subsequent broods. In North-Eastern Europe, old song-thrush nests provide the favoured nest site for green sandpipers.

Swallow and House Martin.Both swallows and martins make their nests from mud pellets, cemented with the bird’s saliva, but although the martin’s nest is a domed construction, built under a ledge, gable or overhang, that of the swallow is an open cup, typically situated on a shelf or beam in a barn or building. Dry springs are a problem for both species: if mud is unavailable, building is impossible. When the mud quality is poor, it often results in the nest collapsing later in the season.

Constructing the nest is labour intensive, with as many as 1,200 journeys needed; most of the work takes place between 6am and 8am, allowing the mud to harden during the day. Both species will adopt artificial nests—a pair of swallows nests in my cart lodge every year, using an artificial nest, usually rearing two broods of five.

Long-tailed tit
According to W. H. Hudson, writing in his classic British Birds (1895), ‘the nest of the long-tailed titmouse is a marvel of bird architecture: a domed oval composed of moss, lichens, and hair closely felted, and the interior thickly lined with feathers. [Victorian ornithologist William] McGillivray says that the feathers from one nest numbered 2,379.’

Long-tailed tits start breeding early in the spring, building among brambles, in gorse or lichen-covered thorn bushes in which the nests are difficult to find. The nests are rarely more than a few feet off the ground. Amusingly, you can spot incubating females because continually squeezing into the confined space of the nest causes their tails to bend and become misshapen

Buzzard
Large, bulky and often conspicuous, the nest of the buzzard is an elaborate affair. The basic nest is made from stout sticks and includes a wide platform around the shallow, lined cup in the centre. The platform allows for the fact that the young buzzards will be in the nest for 6–7 weeks after hatching, giving them plenty of room to move around.

What sets the buzzard apart from other raptors is the birds’ habit of decorating their nest with freshly picked foliage, although some individuals are much keener on such embellishments than others. Anything from sprays of rowan leaves to young fronds
of bracken may be used.