Patent Application
20180228094
The application relates generally to a tree frame and grate system and a method to promote the healthy development of newly planted vegetation within primarily impervious surface areas such as sidewalks, street plantings, plazas, parking lots and the like. The design of this system and method would allow the tree to capture rainwater and surface runoff from adjoining impervious surfaces.
Vegetation planting within predominantly paved areas is typically completed as part of new construction such as street improvements, sidewalk and/or parking lot installations, plazas, promenades, or rehabilitation of existing infrastructure. When associated with city streets and public spaces, these collective improvements are sometimes referred to as “streetscapes.” In these scenarios, trees are often incorporated to lend “greening” to an otherwise predominantly concrete or asphalt paved landscape. The addition of vegetation provides aesthetic appeal as well as shading and cooling from the hot sun, when trees are included.
During construction activities as part of these infrastructure improvement activities, heavy earth moving equipment is necessary and relied upon to re-shape and grade the land surface, as well as to install necessary utilities such as water, sewer, electricity, and other infrastructure. The continuous operation of equipment over the unpaved ground surface, causes severe compaction of existing soil.
During construction in many urban landscapes, buried rubble and debris from previous activities are often encountered. This debris, as well as any newly accumulated debris is typically left in place or buried at shallow depths. Once the infrastructure has been installed, and streets and sidewalks are paved and poured, new tree planting takes place, typically in predetermined and preserved exposed openings a/k/a tree pits, within newly poured sidewalks, or in small islands within a sea of impervious surface. The openings may be square, rectangular, or round, with dimensions of typically less than 20 square feet or three feet in diameter respectively, and usually contain the same compacted or otherwise unimproved soils as surrounding areas. These openings and dimensions are typically designed to accommodate the dimensions of a manufactured steel or cast-iron frame and grate system to surround the vegetation providing both aesthetics and pedestrian protection from the open ground surface. If conventional frame and grate units are to be installed, forming and additional concrete pouring is required which could further impact the planting soils. Therefore, the design and installation of sidewalk systems is usually completed at the expense of creating and maintaining a healthy growing environment for plant systems. Consideration or provisions for the acclimation and health of the newly planted vegetation in these otherwise inhospitable environments are often sacrificed.
Paved (impervious) surfaces restrict the exchange of water, oxygen, and nutrients which normally takes place in non-impervious landscapes. These conditions are further compounded by the compaction of soil during construction activities which alters the structure of the soil particles removing air and water holding pockets within the aggregate complex. As mentioned previously, soil compaction is necessary to adequately support sidewalks and pavement, however, it interferes with the requirements of urban trees for sufficient rooting space to support healthy tree growth. Streetscapes which are often planted with street trees, are designed to withstand the compaction necessary for pavement stability for pedestrian and/or traffic loading, yet they may not provide ample rooting area vital to a tree's growth and survival, particularly if the soils are structurally poor or of limited areal dimension.
Roots are opportunistic and will seek out and grow where conditions provide adequate moisture (irrigation), nutrients, and equally important, oxygen. When roots extend beyond their initial planting holes, they usually seek out soil areas of lesser compaction where moisture and oxygen levels are the greatest. In the urban environment, oftentimes, the greatest concentration of moisture and oxygen can be found in the aggregate matrix layer just below the base of a sidewalk slab or paved surface. These areas may include more porous sands and gravel commonly installed directly beneath pavement, or used with subsurface infrastructure such as utility lines to provide structural support. Consequently, vegetation roots may take up primary residence in this preferential layer. This layer often contains enough voids with moisture and oxygen to allow for preferential root growth, however, it may become excessively dry during periods of drought or little rainwater penetration. In addition, without sufficient rooting area beyond and below this layer, roots, particularly the roots of trees, may cause sidewalk failure in the form of cracking and uplifting. When this occurs, the roots are usually directly below the concrete slab of the sidewalk and may be the only area where moisture and air can be consistently available at levels conducive to root growth, particularly when the underlying layers are compacted to a level which usually prevents root penetration.
Because lack of “usable soil” for rooting space is arguably the most limiting factor affecting a street vegetation water, oxygen, and nutrient demands over time, urban trees need to have access to non-compacted soil if they are to achieve the size, function, and benefits for which we desire them. Urban soil compaction generally occurs in what would be the vegetation's preferential rooting zone: the shallow lens of soil typically no greater than three feet deep and ideally extending beyond the tree's canopy. Compaction contributes to insufficient rooting volumes by increasing the soil's bulk density and soil strength to levels producing a tight aggregate with little porosity thus greatly reducing moisture and oxygen storage, factors which greatly restrict root growth.
While several reasons for densification and compaction of urban soils exist, the most common problem is the aforementioned compaction of the soil surrounding a street tree by heavy equipment to install and support pavement or nearby structures. Compaction is necessary as a cost-effective way to increase the strength and stability of existing soil materials to prevent their settlement under or around designed structures. It increases the bearing capacity of the materials below the pavement system and reduces the shrinking and swelling of soils that occurs with water movement or frost action. Therefore, efforts to increase the usable rooting area for street trees within primarily impervious environments, must account for the probability that compaction will take place as a necessity to safely design pavement systems.
Street vegetation in impervious settings in urbanized environments require a certain volume of soil to become established, grow healthy, and attain stature. Large trees in urban settings rarely, if ever, have sufficient soil volume to grow to their full potential size. Many models for predicting the volume of soil required for unrestricted growth have been proposed by the scientific and landscape communities. A reliable measure in many temperate regions is that each inch of the diameter of a tree trunk at approximately four and one-half feet above the ground, requires about 20-25 ft2 of open ground with non-compacted soil. However, this amount of soil is rarely provided in the urban landscape. Trees do survive, but do not reach their expected size. A tree may establish and grow normally for several years, then, when there is no longer enough soil for the tree's increasing size, growth dramatically slows and the tree may be stunted and decline prematurely. Although a discussion of the prescribed volume of soil that is required by an urban tree is beyond the scope and intent of the present invention, the volume of usable soil is directly proportionate to its health and maturation. This is even more important in the acclimation and establishment of a newly planted tree.
Urban vegetation, and in particular “street trees,” in areas with primarily impervious surrounding surfaces, are typically known to have higher mortality rates and lower average lifespans as compared to trees planted in the natural (less impervious) surfaces. Some botanists and urban foresters have reported that many city trees have an average lifespan of 7 years, compared to 32 years for suburban trees. Botanists agree that the average lifespan of urban street trees is 13 years compared with 37 years for residential trees and 150 years for rural trees, however, a wider range of street tree lifespans has been reported from field-based studies. Trees along Boston, Mass. sidewalks, for instance, were estimated to have an average lifespan of approximately 10 years (Foster and Blaine, (1978), J Arboricul, 4(1):14-7) while the estimated average lifespan for urban trees in Baltimore, Maryland has been determined to be 15 years (Nowak et al., (2004), Urban For Urban Green, 2(3):139-47). Although different species and planting locations may be expected to have a range of tree lifespans, overall conclusions are that urban, city, and street trees typically have a much shorter lifespan and earlier mortality than their rural counterparts.
Earth formation and natural geology is non-selective: the soils that lie across and below the earth's surface are not of our design and are highly variable. Many native soils are severely compacted by nature, due to extensive quantities of clays, silts and other fine minerals which are held tightly and bind up and close potential voids thereby reducing moisture and oxygen holding capacity. From a plant growing standpoint, and that of soil nomenclature and classification, what is referred to as “sandy loam” is a soil class considered the most conducive to productive plant growth and root development. Sandy loam is a very open and porous soil, generous in voids which allow for moisture and oxygen storage, essential for the strong development of most plants. These soils are typically more resistant to compaction even under conditions of heavy construction loading and paving then those which are comprised of greater quantities of silt and clay.
The capacity to “engineer” soil allows creates and blends beneficial aggregate mix designed for structural loading and support, as well as providing the essential porosity for successful plant growth. These medias are primarily composed of coarse grained inorganic materials to allow for rapid infiltration, and lesser quantities of organic materials which retain water within the media to provide irrigation for plants. When both inorganic and organic constituents are blended in correct proportions, the resulting engineered media provides a proper balance of high infiltration capacity coupled with sufficient water holding capacity. Additionally, when the greater of the two proportions are comprised of aggregates of primarily well graded sand, structural loading to support pavement systems is enhanced and achieved.
Recent studies have determined that the incorporation of specific manufactured products or reconstituted rock-based materials formed by expanding specific minerals under intense heat, often referred to as “ceramics” into an engineered media, has the capacity to adsorb and/or absorb (sorption) nutrients commonly found in street runoff following a rain event. Sorption occurs as a chemical or physical bonding process where nutrients become “attached” to a material as it passes in aqueous solution. Excessive concentrations of specific nutrients such as nitrogen, phosphorus, and soluble metals are known to pollute soils and water bodies. However, lesser concentrations of both nitrogen and phosphorus (both essential nutrients for plant health and development) in storm water that reaches a street tree could provide a valued benefit to the health and vigor of the tree if both are bioavailable, being utilized by the plant as a nutrient source.
Other manufactured products such as activated alumina and activated iron have shown a great affinity for the sorption of soluble phosphorus and other minerals in the aqueous stage. The incorporation of these materials in an engineered media have also shown to provide sorption sites to attract these nutrients, potentially rendering them bioavailable to the plant. Ceramics such as expanded shale and expanded clay have also shown a propensity for adsorbing minerals such as phosphorus and nitrogen. The mechanism for this sorption reaction is due mainly in part to the presence of tiny holes and fissures within the ceramic structure. These openings are the result of the artificially induced intense heating of the expanded rock during the manufacturing process that causes the material to “pop”, and forming these openings.
Incorporating any of these manufactured products including, activated alumina, activated iron, or reconstituted rock at no greater than 50% (±5%) by volume with a sand aggregate at no less than 50% (±5) by volume would be expected to provide a nutrient benefit to the plant, as well as enhanced structural support for pavement systems.
In the past 20 years, manufactured products have emerged designed to support pavement systems while reducing the potential for soil compaction in support of street trees. Commercially available products currently exist such as open cell plastic modular chambers that lessen the effects of severe compaction. These chambers have a lattice structure which provides load bearing capabilities and support for soils, thereby resisting the occurrence of compaction. The chambers are typically of smaller dimension (less than 5 square feet), and are designed to be integrated or stackable in multiple units both vertically and horizontally, primarily encompassing the tree's root zone. They do provide benefit in reducing the potential for soil compaction as well as structural support for overlying pavement, however, they present a significant cost in both materials and labor in installation, particularly if new soils are necessary in the reconstruction process.
What are referred to as “structural soils” which are engineered to provide greater porosity and structural support, were also developed over the last two decades and are commercially available. They are formulated with a combination of large particle stone and fine clays with the inclusion of polymers to provide aggregate adhesion and water holding capabilities. Due to the large particle stone matrix, structural soils provide a tremendous advantage in increasing soil porosity, and therefore, water storage and availability. However, due to the large open spaces between the stone particles, these soils tend to readily drain and dry out faster than other soils (both natural and engineered) particularly if the underlying layers of native soils also infiltrate at a rapid rate. During intervening dry periods between rain events, plant roots may suffer due to moisture drought. Due to this potential for greater soil drying and desiccation, particularly in close proximity to the open and exposed area near the base of the tree, structural soils are often recommended to be primarily utilized a distance away from the plant center or trunk of a tree.
A need exists for a preformed frame and grate system and engineered media for encouraging healthy and abundant root growth and permitting optimal development and growth of a tree or other plant material within an urban or otherwise primarily paved environment. It would also be desirable if a potential system could integrate with standard manufactured tree grates that currently exist. Tree frame and grate products such as those manufactured by Neenah Foundry (Neenah, Wis.) are typically comprised of stand-alone, metal-based components solely intended to be set in place at the time of pavement construction and the pouring of concrete. Unless specifically instructed in a project construction plan, soils are not typically improved prior to tree installation and are similarly compacted and/or may contain construction material or urban fill as adjacent soils. A hole is dug which approximates or is somewhat larger than the dimensions of the tree's root ball (typically less the 12 square feet), the tree is then planted in these tree pits. Since the elevation of these conventionally planted trees are at the same elevation of the sidewalk surface or slightly less, their roots are susceptible to migrating horizontally and just below the base of the sidewalk particularly if porous sand or gravel was used as a substrate to support the pavement. If this takes place, over time, sidewalk upheaval may occur. In addition, if the soil surface in these tree pits is at equal elevation as the surrounding pavement, they would not have the opportunity to capture additional rainwater runoff from the adjacent pavement.
Several advantages to the present invention as to be detailed in the following description are designed to rectify the perceived deficiencies in current tree growing systems in highly impervious areas, as well as provide additional benefit. Some of these advantages include healthier tree growth, root redirection to minimize pavement upheaval, rainwater runoff capture, versatility in the integration of tree grates, and an impermeable or substantially impermeable subsurface liner to provide an enclosed treatment area. These and other advantages will become apparent from a consideration of the following description and accompanying drawings.
The present invention is directed to a tree frame and grate system designed to encourage healthy and abundant root growth as well as permitting optimal development and growth of vegetation within an urban landscape. The system is designed to encourage the collection and retention of rainwater, particularly in an arid environment to provide continuous irrigation of vegetation. The system is also designed to maximize the amount of water available to vegetation in a primarily paved environment. The system is comprised of a pre-formed supporting frame to contain an engineered growing media and plant material which may extend beyond the exterior of the supporting frame.
Another embodiment of the invention is directed to an engineered media formulated to promote healthy growth of the plant material and resist compaction from overlying pavement.
A further aspect of the claimed invention includes a method for extending the life-span of vegetation by promoting abundant root growth, in particular, encouraging the development and growth of a tree or other plant material within an urban or otherwise primarily paved environment.
In another embodiment, a tree frame and grate system supporting a customized grate or other partial enclosure, is provided.
Yet another embodiment is directed to a tree frame and grate system adapted for electrical service connection for aesthetic lighting, background sound and the like, as well as piping to provide supplement irrigation.
These renderings and images are included for illustrative and interpretive purposes relative to specific embodiments and applications and should not be construed as the sole positioning, configurations, or singular use of the present invention.
The following terms are defined to aid the reader in fully understanding the operation, function, and utility of the present invention.
“±5%” as used herein, refers to the possibility that the stated amount may vary by 5%. For instance, 100±5%, indicates that the claimed value may range from 95 to 105.
“And/or” as used herein, refers to the possibility that both items or one or the other are claimed. For instance, A and/or B refers to the possibility of A only, B only or both A and B are present in the claimed invention.
“Aggregate” as used herein, refers to a sum, mass, or assemblage of various loose particles of inorganic and/or organic matter of various size and dimension. Furthermore, an “aggregate matrix layer” would represent a distinct or discreet layer of the sum of one or more aggregates.
“ASTM” as used herein, refers to American Society for Testing Materials.
“Bioavailable” as used herein, refers to the extent to which a nutrient or other substance is taken up by a plant's root system to be metabolized and therefore provide growth enhancement to the plant, (e.g., nitrogen, phosphorus, fertilizer, etc.).
“Bulk density” as used herein, is the weight of aggregates in a given volume. Aggregates with greater bulk densities tend to restrict root growth when compacted, particularly in greater concentrations of finer particles are present.
“Canopy” as used herein with respect to trees, refers to the extent of the outer layer of leaves of an individual tree or group of trees.
“Engineered media” as used herein, refers to a growing media specifically formulated, blended, and designed to provide enhanced growing characteristics such as moisture and oxygen retention, nutrient sorption, infiltration capacity, and other attributes to enable the plant material to reach its fullest potential for establishment and growth.
“Impervious/impermeable” as used herein, collectively are terms to describe surfaces that are mainly artificial structures—such as pavements (roads, sidewalks, driveways and parking lots) that are covered by impenetrable materials such as asphalt, concrete, brick, stone. Compacted soils may also be termed, impervious or impermeable.
“Impermeable subsurface membrane liner” as used herein, refers to a synthetic, flexible material which acts as a barrier to separate and maintain segregation between two discrete layers of inorganic and/or organic materials thus preventing the infiltration of water between the two layers.
“Notch” as used herein, is a slightly lower level or recessed surface within the top sidewall of the frame of the present invention which allows for the setting and support of a grate or plate while maintaining equal elevation of both the top surface of the grate or plate and the surface of the top sidewall.
“Porosity” as used herein, refers to the quantity of pores, or open space between aggregate particles. Pore spaces may be a function of the size and shape of various aggregate particles, and how they integrate or connect as a mass, or can be formed or expanded due to the movement of roots. The differences in the size and shape of the aggregates influence the way they fit together, and thus their porosity.
“Plants” or “vegetation” as used herein, is a collective term for a living organism of the kind exemplified by trees, shrubs, herbs, grasses, ferns, and mosses, typically growing in a permanent site, absorbing water, oxygen, and nutrients through its roots.
“Semi-impermeable subsurface membrane liner” as used herein, refers to a synthetic, flexible material which acts as a porous barrier to separate and maintain segregation between two discrete layers of inorganic and/or organic materials thus allowing for the controlled flow of water between the two layers.
“Sorption” as used herein, is a collective term for both absorption and adsorption considered as a single process.
“Streetscape” as used herein, refers to the visual elements of a street, including the road, adjoining buildings, sidewalks, street furniture, trees and open spaces, etc., that combine to form the street's character.
“Sump” as used herein, refers to a pit or hollow in which liquid collects.
“Tree pit” as used herein, refers to the hole in the ground in which a tree is planted. In the urban context, the pit may represent the areal dimension of open non-impervious space within an otherwise impervious pavement surface.
“Urban” as used herein, relates to, or is characteristic of a city or town particularly that where the ground surface is primarily paved and impervious.
As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having” or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
Also, use of the “a” or “an” are employed to describe elements and components of the invention. This is done merely for convenience and to give a general sense of the invention. This description should be read to include one or at least one and the singular also includes the plural unless it is obvious that it is meant otherwise.
Reference throughout this specification to “plant(s)”, “tree(s)”, “vegetation”, or “roots” is used. One skilled in the art will recognize that embodiments of the invention should not be limited to these terms and that the terms herein are interchangeable or in general association for any tree, plant, root, or other vegetation that would benefit from the described invention.
The present invention is intended to be a combined tree frame and grate system whereby plant material such as trees can better survive and thrive in a primarily impervious surface environment. More particularly, the invention is intended to allow for the flexibility in utilizing multiple shapes and dimensions of manufactured tree grates. Attention is also given to a system which is comprised of an engineered media that provides greater moisture holding capacity and nutrient sorption, while providing structural support for pavement systems.
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Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.
In the above description, numerous specific details are provided, such as the identification of various system components, to provide an understanding of embodiments of the invention. One skilled in the art will recognize, however, that embodiments of the invention can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In still other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of various embodiments of the invention. Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.
The descriptions and drawings should be assumed as illustrative only of the principles of the invention. The invention may be configured in a variety of shapes and sizes and is not limited by the aforementioned dimensions, construction and operation of the identified parts, materials or embodiments. It is understood that numerous modifications, changes, and substitutions of the invention will readily occur to those skilled in the art and may be resorted to falling within the scope and spirit of the invention.
While the previous description contains many specifics, these should not be construed as limitations on the scope of the invention, but as exemplifications of the presently preferred embodiments thereof. Thus, the scope of the invention should be determined by the appended claims and their legal equivalents. It is not desired to be limited to the exact details of construction shown and described for obvious modifications will occur to a person skilled in the art, without departing from the spirit and scope of the appended claims.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.
This application is a continuation-in-part application of pending U.S. Ser. No. 15/752,888 filed Feb. 14, 2018 which is a continuation under 35 U.S.C. § 371 of PCT/US2016/051205 filed on Sep. 11, 2016 which claims priority to and the benefit of U.S. Provisional Patent Application No. 62/217,241 filed Sep. 11, 2015 and U.S. Provisional Patent Application No. 62/217,224 filed Sep. 11, 2015, the entire contents of each are incorporated by reference herein.
| Number | Date | Country | |
|---|---|---|---|
| 62217224 | Sep 2015 | US | |
| 62217241 | Sep 2015 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15752888 | Feb 2018 | US |
| Child | 15944228 | US |
