Here are some very interesting articles I found regarding inherent problems with hardwood mulches - robbing Nitrogen and Artillery Fungus. Be sure to read about the Artilery (Shotgun) Fungus: http://www.gardensalive.com/article.asp?ai=766&bhcd2=1176401499 http://ohioline.osu.edu/hyg-fact/3000/3304.html http://aginfo.psu.edu/news/july97/fungus.html http://aginfo.psu.edu/PSA/ws2000/green5.html "Hardwood tree bark (oak, maple, etc.), even from large trees, contains a large concentration of cellulose that is not protected from rotting. Therefore, hardwood bark mulches, like ground wood from almost all tree species, rot readily and cause most of the nuisance mold problems in the landscape. The finer the product is ground, the more severe the problem can be! These materials are low in nitrogen content. The fine particles (less than 3/4" diameter) in such mulches cause nitrogen immobilization in soil. The microflora that decomposes the wood particles takes up the nitrogen required for growth of plants. The result is that the plant becomes starved for nitrogen. Some mulch producers screen all particles smaller than 3/8" out of high-wood-content or hardwood-bark mulches, which avoids most of the nitrogen immobilization problem. The best way to avoid all these problems and bring about beneficial effects by mulching is to add nitrogen to woody and hardwood bark products followed by composting to lower the carbon to nitrogen ratio. Blending of grass clippings with wood wastes before composting is one way to achieve this. Addition of poultry manure or urea to supply 1.2 lbs. available nitrogen per cubic yard of material satisfies the nitrogen need also. Some landscapers add 10-15% by volume composted sewage sludge to hardwood bark or wood wastes, and this makes an ideal product that has performed very well in landscapes. These amended products should be composted at least six weeks. This process kills plant pathogens, eggs of insect pests, and produces a nitrified product that releases plant nutrients rather than ties up nitrogen. As mentioned above, the microorganisms that have colonized these products reduce the potential for growth of nuisance fungi and provide control of many plant diseases."

From what you say it seems the landscape fabric has outlived its usefulness. On one hand it's not deterring weeds anymore since the deep mulch itself is doing that, but on the other hand it's not really hurting anything by staying there except maybe deterring the earth worms from traveling up and down in the different layers of soil depending on the temperature and moisture. I'd be inclinded to take it out to allow, as you say, the mulch (and the earthworms) to benefit the deeper layers of soil in which the tree roots grow. Like Melva the only place I have it is under pea gravel areas. Happy gardening!

Organic Weed Control Methods ~ Mulching What is Mulch?" Mulch is a protective covering (such as of bark chips, compost, or grass clippings) overlaid on the ground. Mulch reduces the moisture loss from the soil by preventing evaporation from sunshine and desiccating winds. Mulch prevents erosion by eliminating or reducing the "splash-away" effect of torrential downpours. Mulch helps regulate soil temperature by shading it in the summer thus keeping it cooler and helps insulate it in the winter from chilling winds. This temperature regulating effect helps encourage the root growth of plants. Mulch helps to keep fruit clean (such as strawberries and tomatoes) by reducing muddy splash-ups during rainstorms. Mulch controls weed growth by smothering seedlings, prevents daylight which helps foster germination from reaching weed seeds, and prevents air-borne seeds from taking hold in the soil surface. Mulch helps prevent damage to trees and bushes by protecting their stems and surface roots from damage by mechanical garden tools such as weed whackers, edgers, and lawn mowers. Mulch helps prevent soil compaction by providing a cushion to walk upon. Walking on bare soil will compact it reducing its aeration and ability to drain. Mulch provides a more unified and tidy appearance to flower beds and borders. Mulch helps reduce yardwaste disposal and cash outlay. If you utilize your own yard wastes by chipping pruned branches and limbs, make your own compost, or use grass clippings and raked fallen leaves for mulch you won't have to bag and haul them to the curb for collection or pay for their disposal, you won't utilize land-fill space, and you'll keep your wallet in your pocket because the mulch you create is free. Mulch enriches the soil as it breaks down and releases nutrients back into the ground. Mulch, if not already decomposed, will encourage microbial organisms which are beneficial to healthy plants. ++++++++++++++++++++++++++++++++++++++++++++++++ "What are some common mulches?" Chipped hardwood bark mulch: Is readily available for home-owners from township landfills. It is made from ground and/or chipped trees. It is often free or available at a low cost. The downside of chipped bark mulch from municipalities is that it may contain bark from diseased trees. Compost it for a year before using it in your garden. Before you apply the aged bark mulch topdress your garden soil with fertilizers high in nitrogen such as blood-meal, cottonseed-meal, manure, or guano. Softwood bark mulch: Made from pine, fir, or redwood, is available in many different sizes. It is long lasting and excellent for use in foundation plantings. Compost: Is an excellent mulch that you can make at home by composting various yardwastes such as leaves, grass clippings, plants and soft-wood bush prunings, coffee grounds, and non-animal kitchen wastes. Partially decomposed composted material is one of the most nutrient rich mulches you can use. As it breaks down it releases nutrients into the soil. Crushed Corncobs: Regionally available inexpensive mulch. It is generally available as a dyed or natural product. Corncob mulch is a cushioning mulch and is often used in playgrounds. Hay: Often used in rural and farm gardens because it is more likely to be available at the least expensive cost. The use of aged bales may reduce the weed content. Apply hay mulch after the ground has warmed to discourage mice and voles from tunneling under it. Spent Hops: Available from breweries. Can be a bit "whiffy" after application but the scent will dissipate after a few weeks. Buckwheat Hulls: Buckwheat hull mulch is fluffy and is excellent for use around perennials and annuals. Cocoa-bean Hulls: Cocoa-bean hull mulch is a rich brown color and smells like chocolate-heaven (yumyum!). Apply it in a thin layer as it can otherwise become slimy or moldy. If applied at greater than a three inch depth you may wish to occasionally rake it to stir the hulls about, thus reducing the dampness which fosters the mold. Peanut Hulls: Peanut hull mulch is available from garden centers near peanut growers and processors. As it breaks down it provides some nitrogen to the soil. Lawn Clippings: Grass clippings are best used after they've been allowed to dry. If applied while they're fresh they can compact and generate heat while decomposing. They can produce strong odors the first week or two of decomposition but the scent will subside after that. It is not recommended to use grass clippings from lawns that have been treated with pesticides, fungicides, or herbicides. Leafmold: This mulch is available from most municipal composting facilities or you can make your own. Autumn gathered leaves left to decompose over winter will provide you with leafmold ready for use the following spring. Fallen Leaves: The least expensive form of mulch available. It is readily available in Autumn near woody areas. Fallen leaves may be used as is, chopped with the lawn mower to reduce their size, or compost them during winter and use them as leafmold the following spring. Manure: Available as a bagged commercially composted product at garden centers, or available fresh from stables and farms. Fresh manure should be composted for at least six months to reduce nitrogen burn when applied around plants and to reduce the viability of weed seeds in the manure itself. Mushroom soil/compost: Is available at garden centers or sources near commercial mushroom growers. It is generally inexpensive. Peat Moss: A commonly used mulch, it is attractive when applied thickly. Look for course-grade peat moss when using it for a mulch. It can be cost prohibitive when used for mulching large areas. Peat moss will shed water when it's dry rather than absorbing it. You can help maintain it's moisture by watering this mulch regularly when you also water your lawn. Pine Needles: Are a light colored, fluffy, and pretty mulch. Leave them in place under pine trees rather than removing them. Rake them from your lawn grass and use them to mulch around acid-loving plants such as azaleas, blueberries, and rhododendrons. They are also excellent to use as a cushioning mulch for garden paths and will release their pine scent when walked upon. Sawdust: Available from timber mills or other wood processing businesses. As it decomposes it can cause nitrogen loss from the the soil so if used in garden beds apply nitrogen rich fertilizers regularly. Sawdust is an excellent mulch for garden paths. It is not recommended to use sawdust from chemically treated or painted wood. Straw: Can be used for winter protection as an overlay in muddy areas and will provide some traction on icy paths. It is also frequently used as a mulch in veggie gardens. Do not use straw mulch in frequently used areas as it is highly inflammable. Do not use it to mulch walkways as it can be easily ignited by a carelessly tossed smoldering cigarette butt. Wood Chips: Can be obtained from arborists, utility companies, municipal yard waste facilites, and garden centers. They are very long lasting and make a good overlayment for paths and walkways. To learn more about mulch and the wonderful effect of compost and micro-organisms in the soil please visit the "Soil, Compost, and Mulch Forum" and do read their fabulous FAQs. Taking care of your soil is vital to having a garden of healthy and vigorous plants.

there is so much wrong in what you said... i can understand your frustration ... first.. newly planted trees ... any plant... needs mulch to cool the soil.. reduce weed competition ... and as a water management system ... it keeps the soil moister.. longer.. especially on hot summer days .... an established tree.. need a mulch ring.. to keep the idiot with the lawnmower and weedwhip away for the tree .. trust me.. i damaged enough trees.. to know why .. lol ... it only took me a decade to learn such ... lol .. otherwise.. its jsut used to make it all look pretty.. see below .... an established tree... is said to be twice as large below ground as above ... though in a different form ... as such.. planting things under it.. will NEVER harm it ... IMHO ... presuming you arent digging holes with a backhoe or some such ... many large old trees are hard to grow under.. because they out compete the new planting for water .. so if you perfect watering .. and a few other tricks ... you can do just about anything you want under them ... though there are some trees... where it isnt even worth the effort.. like a norway maple.. e.g. on a new transplant.. it might be good .. to leave it alone for a few years.. to grow that root mass i spoke of above ... so i would plant too many thing around it .... does this help clarify your thought process.. i could try again.. if not ... as great as the web is.. its really hard.. to hone in on peeps in the same circumstances ... and if you dont know the right terms.. the search brings you so much info ... its bewildering ... and that is why GW can be a great help.. to get you on the right path.. to learn ... i did leave out all discussion of mulch.. using it .... just so it all looks pretty ... using such to make your whole yard.. cohesive.. on some level ... shall i try again??? ken