User:AJEA2000/Woody plant

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A section of rosemary stem, an example of a woody plant, showing a typical wood structure.

Introduction (originally was up to ".. until spring")

A woody plant is a plant that produces wood as its structural tissue and thus has a hard stem. In cold climates, woody plants further survive winter or dry season above ground, as opposed to herbaceous plants that die back to the ground until spring. Woody plants include trees, shrubs, and lianas, and are typically reinforced with wood produced from secondary xylem. This allows them to grow year after year and become some of the largest and tallest terrestrial plants. Woody plants have a dormant period of the year when growth does not take place, which is usually accompanied by the shedding of leaves. In colder climates, most stem growth occurs during spring and early summer. Most woody plants native to colder climates have distinct growth rings produced by each year's production of new vascular tissue. Woody plants can reproduce in various ways, such as seeds, cuttings, and grafting. Woody plants play a crucial role in the ecosystem as they provide habitats, oxygen, and contribute to carbon storage. They also play a significant role in literature, art, and mythology.

Characteristics (sources have been added)

Woody plants: Tallest terrestrial plants

Woody plants are usually trees, shrubs, or lianas. These are usually perennial plants whose stems and larger roots are reinforced with wood produced from secondary xylem. The main stem, larger branches, and roots of these plants are usually covered by a layer of bark. Wood is a structural tissue that allows woody plants to grow from above ground stems year after year, thus making some woody plants the largest and tallest terrestrial plants.

Woody plants, like herbaceous perennials, typically have a dormant period of the year when growth does not take place, in colder climates due to freezing temperatures and lack of daylight during the winter months, in subtropical and tropical climates due to the dry season when precipitation becomes minimal. The dormant period will be accompanied by shedding of leaves if the plant is deciduous. Evergreen plants do not lose all their leaves at once (they instead shed them gradually over the growing season), however growth virtually halts during the dormant season. Many woody plants native to subtropical regions and nearly all native to the tropics are evergreen due to year-round warm temperatures.

During the fall months, each stem in a deciduous plant cuts off the flow of nutrients and water to the leaves. This causes them to change colors as the chlorophyll in the leaves breaks down. Special cells are formed that sever the connection between the leaf and stem, so that it will easily detach. Evergreen plants do not shed their leaves and merely go into a state of low activity during the dormant season. During spring, the roots begin sending nutrients back up to the canopy.

When the growing season resumes, either with warm weather or the wet season, the plant will break bud by sending out new leaf or flower growth. This is accompanied by growth of new stems from buds on the previous season's wood. In colder climates, most stem growth occurs during spring and early summer. When the dormant season begins, the new growth hardens off and becomes woody. Once this happens, the stem will never grow in length again, however it will keep expanding in diameter for the rest of the plant's life.

Most woody plants native to colder climates have distinct growth rings produced by each year's production of new vascular tissue. Only the outer handful of rings contain living tissue (the cambium, xylem, phloem, and sapwood). Inner layers have heartwood, dead tissue that serves merely as structural support.

Growth (sources have been added)

Winter buds on Cercidiphyllum japonicum

Stem growth primarily occurs out of the terminal bud on the tip of the stem. Buds on the sides of the stem are suppressed by the terminal bud and produce less growth, unless it is removed by human or natural action. Without a terminal bud, the side buds will have nothing to suppress them and begin rapidly sending out growth, if cut during spring. By late summer and early autumn, most active growth for the season has ceased and pruning a stem will result in little or no new growth. Winter buds are formed when the dormant season begins. Depending on the plant, these buds contain either new leaf growth, new flowers, or both.

Terminal buds have a stronger dominance on conifers than broadleaf plants, thus conifers will normally grow a single straight trunk without forking or large side or lateral branches.

As a woody plant grows, it will often lose lower leaves and branches as they become shaded out by the canopy. If a given stem is producing an insufficient amount of energy for the plant, the roots will "abort" it by cutting off the flow of water and nutrients, causing it to gradually die.

Below ground, the root system expands each growing season in much the same manner as the stems. The roots grow in length and send out smaller lateral roots. At the end of the growing season, the newly grown roots become woody and cease future length expansion, but will continue to expand in diameter. However, unlike the above-ground portion of the plant, the root system continues to grow, although at a slower rate, throughout the dormant season. In cold-weather climates, root growth will continue as long as temperatures are above 2 °C (36 °F).

Tissue composition (source + image added)

Wood is primarily composed of xylem cells with cell walls made of cellulose and lignin. Xylem is a vascular tissue which moves water and nutrients from the roots to the leaves. Most woody plants form new layers of woody tissue each year, and so increase their stem diameter from year to year, with new wood deposited on the inner side of a vascular cambium layer located immediately beneath the bark. However, in some monocotyledons such as palms and dracaenas, the wood is formed in bundles scattered through the interior of the trunk. Stem diameter increases continuously throughout the growing season and halts during the dormant period.

Under specific conditions, woody plants may decay or may in time become petrified wood.

Symbol

The symbol for a woody plant, based on Species Plantarum by Linnaeus is , which is also the astronomical symbol for the planet Saturn.

Reproduction in Woody plants

Woody plants can reproduce in a variety of ways, including seeds, cuttings, and grafting. Seeds are the most common way for woody plants to reproduce. Cuttings are another common method for propagation, in which a stem or branch is cut from a parent plant and planted in soil or water to grow into a new plant. Grafting involves the joining of two different plant parts to create a new plant. This technique is commonly used in the propagation of fruit trees.

Role of Woody plants in the ecosystem

Woody plants, such as trees and shrubs, are an essential component of our natural environment. From the massive conifer forests to the little, dispersed hardwood groves, they have a significant impact on the physical characteristics (shaping landscape) of our planet. In addition to providing shelter, food, and nesting places, woody trees are an essential component of the ecosystem for a wide variety of animal and plant species. A hugely significant renewable resource for human cultures, woody trees also provide wood for building, fuel, and a variety of other things. Woody plants may continue to create our environment, promote biodiversity, and serve as a source of resources for future generations by being managed and conserved with care.

Uses of Woody plants by Humans

Woody plants have been used by humans for a variety of purposes, including lumber, paper, fuel, and medicine.

Lumber

Lumber

Woody plants have been an essential resource for human civilizations for thousands of years. One of the primary uses of woody plants by humans is as a source of lumber. Wood is used to construct buildings, furniture, tools , and a huge variety of other products. Different types of wood are used for different purposes based on their strength, durability, and appearance. For example, hardwoods such as walnut and maple are used for furniture and flooring, while softwoods such as pine and spruce are used for construction framing and paper production.

Fuel

In addition to them being a source of lumber, they are also a source of fuel. Burning wood for heat is a sustainable alternative because it produces renewable energy, which is particularly important in poor nations. In addition to woody plants usage for fuel, they’re also used to make charcoal, which is commonly used for grilling and barbecuing. Woody biomass, is also used to generate electricity, heat homes, and produce biofuels.

Medicine

Plants used as herbal medicine.

As woody plants contain a variety of chemicals with therapeutic characteristics, humans have used them for medicinal purposes for thousands of years. Aspirin and quinine are two examples of traditional medicines that were first produced from plant sources. Nowadays, woody plants play a crucial role in the production of about 25% of modern medicines. Medicinal substances are found in plants such as ginkgo biloba and their extracts are used to treat a variety of illnesses like Alzheimer's disease. Thus, woody plants are essential for the creation of contemporary medications in addition to being a source of raw materials.

Overall, the uses of woody plants by humans are diverse and numerous, highlighting their importance as a valuable and renewable resource.

Adaptations of Woody plants to their environments

Plants with wooden stems have undergone modifications to survive in diverse environments. One common modification is drought resistance, allowing them to preserve water during arid spells. Another modification is shade tolerance, which facilitates their growth under other trees or structures by adapting their photosynthesis to low-light conditions. Some plants have also developed fire resistance to withstand wildfires.

Woody plant pests and diseases

Leaf spotting caused by diseases

Insects, fungus, and bacteria, as well as other pests and diseases, are attracted to woody plants. Diseases result in leaf spots, and other damages. Pests can wreak havoc on leaves, branches, and roots. Aphids, spider mites, and scale insects are some examples of common pests, whereas powdery mildew and root rot are examples of common illnesses.

Importance of Woody plants

Plants that have a woody stem play a crucial role in the balance of ecosystems due to various reasons. An important aspect is that they offer shelter and sustenance to animals. Moreover, they play a significant role in carbon sequestering, which helps in reducing the impact of climate change. However, these woody plants are currently facing various challenges such as habitat depletion, deforestation, and the consequences of climate change. Some of the tree species are at risk of extinction which could cause catastrophic environmental consequences.

The preservation of woody plants and their surroundings is of great significance, not only in terms of their ecological worth but also for their economic value. The maintenance of forests and the promotion of sustainable forestry practices are vital for the long-term wellbeing of our planet.

Cultural Significance

Over thousands of years, woody trees have played a significant role in human culture. They play a significant role in literature, art, and mythology. Trees are frequently used as metaphors for power, sagacity, and knowledge. They serve as objects of respect and are employed in religious rituals.

In some cultures, trees are believed to be inhabited by spirits or gods.  In others, they are seen as a source of knowledge or inspiration.  The practice of tree planting, or tree adoption, has become a popular way for people to express their love and appreciation for nature.