Lammas growth

Lammas growth, also called Lammas leaves, Lammas flush, second shoots, or summer shoots, is a season of renewed growth in some trees in temperate regions put on in July and August (if in the northern hemisphere, January and February if in the southern), that is around Lammas day, August 1, which is the Celtic harvest festival.

It can occur in both hardwoods and softwoods. Examples of common trees which exhibit regrowth are oak, ash, beech, sycamore, yew, scots pine, sitka spruce and hawthorn. This secondary growth may be an evolutionary strategy to compensate for leaf damage caused by insects during the spring.[1] It is not present in poplar, birch or willow.

Lammas growth declines with the age of the tree, being most vigorous and noticeable in young trees. It differs in nature from spring growth which is fixed when leaves and shoots are laid down in the bud the previous year. The lammas flush is free growth of newly made leaves/needles throughout the tree.[2] One or more of the buds set in the Spring on the ends of terminal and lateral stems will break, and begin to grow, producing a new shoot.[3]

Lammas growth on Q. robur
Lammas growth on a pedunculate oak.

References

  1. ^ Guinness, Bunny (16 Aug 2006). "Late summer growth". The Daily Telegraph. Retrieved 2009-06-03.
  2. ^ Battey, Nicholas H. (2003). "August – learning about summer" (PDF). Journal of Experimental Botany. 54 (389): 1798.
  3. ^ West, Richard F.; Rogers, Robert (1965). "THE EFFECT OF LAMMAS SHOOT GROWTH ON THE STEM FORM OF YOUNG SCOTCH PINE". Published as a Paper of the Journal Series, New Jersey Agricultural Experiment Station.
Heteroblasty (botany)

Heteroblasty is significant and abrupt change in form and function that occurs over the lifespan of certain plants. Characteristics affected include internode length and stem structure as well as leaf form, size and arrangement. It should not be confused with seasonal heterophylly, where early and late growth in a season are markedly different. This change is different from a homoblastic change which is a gradual change or little change at all so that there is little difference between the juvenile and adult stages. Some characteristics affected by heteroblastic change include internode length and stem structure as well as leaf form, size and arrangement. Heteroblasty is found in many different Families as well as different species with in a genus, this random spread of heteroblastic plants across species is believed to be caused by convergent evolution. Heteroblasty should not be confused with seasonal heterophylly, where early and late growth in a growing season are markedly different.The earlier and later stages of development are commonly labeled as juvenile and adult respectively, particularly in relation to leaves.The term was coined by German botanist Karl Ritter von Goebel, along with homoblasty for plants with leaf characteristics that do not change significantly. Leonard Cockayne observed that heteroblasty occurred in an unusually high proportion of tree species native to New Zealand.

Lammas

Lammas Day (Anglo-Saxon hlaf-mas, "loaf-mass"), is a holiday celebrated in some English-speaking countries in the Northern Hemisphere, usually between 1 August and 1 September. It is a festival to mark the annual wheat harvest, and is the first harvest festival of the year. On this day it was customary to bring to church a loaf made from the new crop, which began to be harvested at Lammastide, which falls at the halfway point between the summer Solstice and Autumn September Equinox.

The loaf was blessed, and in Anglo-Saxon England it might be employed afterwards to work magic: a book of Anglo-Saxon charms directed that the lammas bread be broken into four bits, which were to be placed at the four corners of the barn, to protect the garnered grain.

In many parts of England, tenants were bound to present freshly harvested wheat to their landlords on or before the first day of August. In the Anglo-Saxon Chronicle, where it is referred to regularly, it is called "the feast of first fruits". The blessing of first fruits was performed annually in both the Eastern and Western Churches on the first or the sixth of August (the latter being the feast of the Transfiguration of Christ).

Lammas has coincided with the feast of St. Peter in Chains, commemorating St. Peter's miraculous deliverance from prison, but in the liturgical reform of 1969, the feast of St. Alphonsus Liguori was transferred to this day, the day of St. Alphonsus' death.

Shoot

In botany, shoots consist of stems including their appendages, the leaves and lateral buds, flowering stems and flower buds. The new growth from seed germination that grows upward is a shoot where leaves will develop. In the spring, perennial plant shoots are the new growth that grows from the ground in herbaceous plants or the new stem or flower growth that grows on woody plants.

In everyday speech, shoots are often synonymous with stems. Stems, which are an integral component of shoots, provide an axis for buds, fruits, and leaves.

Young shoots are often eaten by animals because the fibres in the new growth have not yet completed secondary cell wall development, making the young shoots softer and easier to chew and digest. As shoots grow and age, the cells develop secondary cell walls that have a hard and tough structure. Some plants (e.g. bracken) produce toxins that make their shoots inedible or less palatable.

Tree

In botany, a tree is a perennial plant with an elongated stem, or trunk, supporting branches and leaves in most species. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are usable as lumber or plants above a specified height. Trees are not a taxonomic group but include a variety of plant species that have independently evolved a woody trunk and branches as a way to tower above other plants to compete for sunlight. Trees tend to be long-lived, some reaching several thousand years old. In wider definitions, the taller palms, tree ferns, bananas, and bamboos are also trees. Trees have been in existence for 370 million years. It is estimated that there are just over 3 trillion mature trees in the world.A tree typically has many secondary branches supported clear of the ground by the trunk. This trunk typically contains woody tissue for strength, and vascular tissue to carry materials from one part of the tree to another. For most trees it is surrounded by a layer of bark which serves as a protective barrier. Below the ground, the roots branch and spread out widely; they serve to anchor the tree and extract moisture and nutrients from the soil. Above ground, the branches divide into smaller branches and shoots. The shoots typically bear leaves, which capture light energy and convert it into sugars by photosynthesis, providing the food for the tree's growth and development.

Trees usually reproduce using seeds. Flowers and fruit may be present, but some trees, such as conifers, instead have pollen cones and seed cones. Palms, bananas, and bamboos also produce seeds, but tree ferns produce spores instead.

Trees play a significant role in reducing erosion and moderating the climate. They remove carbon dioxide from the atmosphere and store large quantities of carbon in their tissues. Trees and forests provide a habitat for many species of animals and plants. Tropical rainforests are among the most biodiverse habitats in the world. Trees provide shade and shelter, timber for construction, fuel for cooking and heating, and fruit for food as well as having many other uses. In parts of the world, forests are shrinking as trees are cleared to increase the amount of land available for agriculture. Because of their longevity and usefulness, trees have always been revered, with sacred groves in various cultures, and they play a role in many of the world's mythologies.

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