mosses use as decompose and cement converted convert into soil

mosses are small flowerless plants that typically grow in dense green clumps or mats, often in damp or shady locations. The individual plants are usually composed of simple leaves that are generally only one cell thick, attached to a stem that may be branched or unbranched and has only a limited role in conducting water and nutrients. Although some species have conducting tissues, these are generally poorly developed and structurally different from similar tissue found in vascular plants. Mosses do not have seeds and after fertilisation develop sporophytes with unbranched stalks topped with single capsules containing spores. They are typically 0.2–10 cm (0.1–3.9 in) tall, though some species are much larger. Dawsonia, the tallest moss in the world, can grow to 50 cm (20 in) in height.

Mosses are commonly confused with lichens, hornworts, and liverworts.Lichens may superficially look like mosses, and have common names that include the word "moss" (e.g., "reindeer moss" or "iceland moss"), but are not related to mosses. Mosses used to be grouped together with the hornworts and liverworts as "non-vascular" plants in the former division "bryophytes", all of them having the haploidgametophyte generation as the dominant phase of the life cycle. This contrasts with the pattern in all vascular plants (seed plants and pteridophytes), where the diploid sporophyte generation is dominant.

Mosses are now classified on their own as the division Bryophyta. There are approximately 12,000 species.

The main commercial significance of mosses is as the main constituent of peat (mostly the genus Sphagnum), although they are also used for decorative purposes, such as in gardens and in the florist trade. Traditional uses of mosses included as insulation and for the ability to absorb liquids up to 20 times their weight.

There is a substantial market in mosses gathered from the wild. The uses for intact moss are principally in the florist trade and for home decoration. Decaying moss in the genus Sphagnum is also the major component of peat, which is "mined" for use as a fuel, as a horticultural soil additive, and in smoking malt in the production of Scotch whisky.

Sphagnum moss, generally the species S. cristatum and S. subnitens, is harvested while still growing and is dried out to be used in nurseries and horticulture as a plant growing medium.

The practice of harvesting peat moss should not be confused with the harvesting of moss peat. Peat moss can be harvested on a sustainable basis and managed so that regrowth is allowed, whereas the harvesting of moss peat is generally considered to cause significant environmental damage as the peat is stripped with little or no chance of recovery.
mosses perform very useful function in nature .they provide shelter for other organism like earth warm. when it grow on rocks or cemented area ,the chemicals that release contribute  to the slow process of cement breakdown and soil formation.