patrickbdevaney/mia9 · Datasets at Hugging Face

text stringlengths 0 6.44k
between pine rockland EEL sites and other natural areas by creation of greenways,
acquisition and restoration of vacant land between parcels, and encouraging
appropriate zoning around and between parcels.
Miami-Dade County pineland with adjacent development
Photo by Keith Bradley, IRC
EEL Program, Management Plan, Part II – Pine Rockland (DRAFT) _____________________________________________________________________________________________________________________
Page 31
preferred. If residential development is planned around EEL sites, larger lot sizes such as EU-2
(5 acres) and EU-1C (2.5 acres), are much preferred over small lots (all RU types), to maximize
open space and limit pollution runoff. Construction of hospitals, schools, apartments, and hotels
around EEL sites should be discouraged because of conflicts with smoke generation during
prescribed fires. In support of this, the EEL program should develop a map of smoke corridors
for EEL properties during prescribed burning, which the Miami-Dade County Planning and
Zoning Department could utilize to more effectively plan zoning and natural areas protection in
these areas.
4.3 Targets for Vegetation Structure
Historical and current vegetation conditions have been discussed in Sections 2.4 and 3.4,
respectively. This section discusses management of vegetation structure and composition. In
general, pine rockland sites should be managed in an attempt to restore or approach historical
conditions. Some aspects of vegetation may need to be managed outside of historical parameters
to deal with the constraints imposed on management by extremely fragmented forest conditions.
4.3.1 Canopy Density
Pine rocklands should be managed to retain a canopy of South Florida slash pine and hardwoods
should not be allowed to reach canopy stature. Historical densities of pines in pine rocklands
ranged from about 200 to 900 per acre (Snyder et al., 1990, Platt et al. 2002). However, due to
reduced fire frequency, pine rockland sites should be managed for a sparser canopy of pines than
they historically had, perhaps ranging from 25 to 225 trees per hectare, a quarter of the historic
density.
Reduced pine canopies are now desirable because future fire frequencies, though targeted to
occur at three (3) to seven (7) year intervals, will likely occur much less frequently than planned.
Because of neighboring structures, roads and highways, and dense populations, some pine
rockland sites may be impractical to burn at all. Pine trees generate large amounts of needle duff
which is normally consumed by fires. In the absence of regular fires the duff accumulates,
decomposes, and creates an organic soil layer. Under this scenario some native pine rockland
herbs and grasses, including endemics and imperiled species, disappear. Remaining pine
rockland fragments with dense pine canopies have a greatly reduced herb diversity. Even if sites
do burn occasionally, but less frequently than three (3) to seven (7) years, herbaceous richness
will decline and when fires do occur they will generate more heat. These more intense fires are
more likely to kill pines and other desirable species.
Experimentation will be required to determine appropriate densities. At some sites with dense
canopy trees or saplings, trees should be removed to achieve lower densities. Prescribed fires
may also be used to reduce densities of sapling pine trees. Conversely, some pine rockland sites
Management Policy
Pine rockland EEL sites shall be managed in an attempt to restore or approach
historical vegetative structure conditions, including the management of canopy
density, understory density, herb layer density and diversity, and exotics at preserve
edges.
EEL Program, Management Plan, Part II – Pine Rockland (DRAFT) _____________________________________________________________________________________________________________________
Page 32
may need pine reintroductions or augmentations to reach target densities. Pines can be planted as
tubelings or directly seeded (Mayo 2000). If using tubelings, pine plantings on a single site
should be sparser than needed for target densities. Periodic plantings at intervals of five (5) to ten
(10) years should be used to achieve target densities to achieve a multi-aged pine stand. If using
seeds, the seed source should be local, preferably from Miami-Dade County. As has been done in
the past, all pines currently utilized for reintroductions or augmentations on pine rockland EEL
sites, whether tubelings or seeds, should originate from local sources.
4.3.2 Understory Density
Understory vegetation densities should be managed in an effort to attain historical conditions. As
noted previously, understory heights were probably less than two (2) feet and overall shrub and
palm cover less than 25%. Ludlum Pineland serves as an example of a site that is probably close
to desired conditions.
Reaching this condition would require hardwood and palm reduction at most pine rockland sites,
preferably by prescribed fire or mechanical removal followed by prescribed fire. Reduction of
understory densities, including hardwoods and palms, would result in better conditions for
prescribed fire. With less fuel, fires are easier to control, produce much less smoke, have less
chance of reaching the pine canopy, and result in lower fire temperatures that may be beneficial
to native herbs and make sites less prone to invasion by exotic and ruderal plant species. While
not preferred, in the absence of fire, manual or mechanical removal, herbicide application, or a
combination of techniques could be utilized to manage understory density in pine rocklands.
4.3.3 Herb Layer
Herb layers should be managed to have a diversity of native species that are indigenous to the
pine rockland community. Following recommended canopy (see Section 4.3.1) and subcanopy
(see Section 4.3.2) management guidelines should be sufficient at most sites to achieve a desired
dense and diverse herb layer. A density target is not provided here because herb layer density
and composition is so variable in pine rocklands. Canopy and subcanopy management focuses
primarily on restoring the historical fire regime at pine rocklands. Reintroduction or
augmentation of native grasses and forbs may be required at some sites. The details of this
practices will be included at the site-specific plans level in Part III of this document.
At pine rockland sites that have been subjected to fire suppression, the diversity of forbs, grasses,
and sedges can be greatly reduced. Following treatment of the canopy and subcanopy, and
reintroduction of fire, many species may reappear from a soil seed bank or dormant roots.
Following restoration by prescribed burning, many fire-suppressed sites would benefit from the
replanting of native herbs. Native species should be used that were historically on or in the
vicinity of the pine rockland fragment being restored. Lists of appropriate species can be found
online at www.regionalconservation.org in the Natives for Your Neighborhood and Floristic
Inventory of South Florida databases. Any reintroductions or augmentations should use
germplasm from pine rocklands as close to the introduction site as possible to ensure that similar
genetic material is used.
EEL Program, Management Plan, Part II – Pine Rockland (DRAFT) _____________________________________________________________________________________________________________________
Page 33
If the application of prescribed fire is absolutely impossible, there are several alternatives that are
available, although less desirable. These options include grazing, herbicide application, and
mechanical treatment. The benefits and disadvantages of these alternatives are detailed in
Section 4.6.4 of this management plan, Alternatives to Prescribed Burning.
4.3.4 Edges
Edges of pine rocklands should be managed to eliminate the occurrence of exotic pest plants
(especially Brazilian pepper, Burma reed, and natal grass) and minimize ruderal species that may
invade pine rocklands after fires.
Open areas with exposed limestone at the edges of pine rocklands (such as fire breaks) can often
be refugia for pine rockland herbs where habitat quality has degraded in the interior of sites.

between pine rockland EEL sites and other natural areas by creation of greenways,

acquisition and restoration of vacant land between parcels, and encouraging

appropriate zoning around and between parcels.

Miami-Dade County pineland with adjacent development

Photo by Keith Bradley, IRC

EEL Program, Management Plan, Part II – Pine Rockland (DRAFT) _____________________________________________________________________________________________________________________

Page 31

preferred. If residential development is planned around EEL sites, larger lot sizes such as EU-2

(5 acres) and EU-1C (2.5 acres), are much preferred over small lots (all RU types), to maximize

open space and limit pollution runoff. Construction of hospitals, schools, apartments, and hotels

around EEL sites should be discouraged because of conflicts with smoke generation during

prescribed fires. In support of this, the EEL program should develop a map of smoke corridors

for EEL properties during prescribed burning, which the Miami-Dade County Planning and

Zoning Department could utilize to more effectively plan zoning and natural areas protection in

these areas.

4.3 Targets for Vegetation Structure

Historical and current vegetation conditions have been discussed in Sections 2.4 and 3.4,

respectively. This section discusses management of vegetation structure and composition. In

general, pine rockland sites should be managed in an attempt to restore or approach historical

conditions. Some aspects of vegetation may need to be managed outside of historical parameters

to deal with the constraints imposed on management by extremely fragmented forest conditions.

4.3.1 Canopy Density

Pine rocklands should be managed to retain a canopy of South Florida slash pine and hardwoods

should not be allowed to reach canopy stature. Historical densities of pines in pine rocklands

ranged from about 200 to 900 per acre (Snyder et al., 1990, Platt et al. 2002). However, due to

reduced fire frequency, pine rockland sites should be managed for a sparser canopy of pines than

they historically had, perhaps ranging from 25 to 225 trees per hectare, a quarter of the historic

density.

Reduced pine canopies are now desirable because future fire frequencies, though targeted to

occur at three (3) to seven (7) year intervals, will likely occur much less frequently than planned.

Because of neighboring structures, roads and highways, and dense populations, some pine

rockland sites may be impractical to burn at all. Pine trees generate large amounts of needle duff

which is normally consumed by fires. In the absence of regular fires the duff accumulates,

decomposes, and creates an organic soil layer. Under this scenario some native pine rockland

herbs and grasses, including endemics and imperiled species, disappear. Remaining pine

rockland fragments with dense pine canopies have a greatly reduced herb diversity. Even if sites

do burn occasionally, but less frequently than three (3) to seven (7) years, herbaceous richness

will decline and when fires do occur they will generate more heat. These more intense fires are

more likely to kill pines and other desirable species.

Experimentation will be required to determine appropriate densities. At some sites with dense

canopy trees or saplings, trees should be removed to achieve lower densities. Prescribed fires

may also be used to reduce densities of sapling pine trees. Conversely, some pine rockland sites

Management Policy

Pine rockland EEL sites shall be managed in an attempt to restore or approach

historical vegetative structure conditions, including the management of canopy

density, understory density, herb layer density and diversity, and exotics at preserve

edges.

EEL Program, Management Plan, Part II – Pine Rockland (DRAFT) _____________________________________________________________________________________________________________________

Page 32

may need pine reintroductions or augmentations to reach target densities. Pines can be planted as

tubelings or directly seeded (Mayo 2000). If using tubelings, pine plantings on a single site

should be sparser than needed for target densities. Periodic plantings at intervals of five (5) to ten

(10) years should be used to achieve target densities to achieve a multi-aged pine stand. If using

seeds, the seed source should be local, preferably from Miami-Dade County. As has been done in

the past, all pines currently utilized for reintroductions or augmentations on pine rockland EEL

sites, whether tubelings or seeds, should originate from local sources.

4.3.2 Understory Density

Understory vegetation densities should be managed in an effort to attain historical conditions. As

noted previously, understory heights were probably less than two (2) feet and overall shrub and

palm cover less than 25%. Ludlum Pineland serves as an example of a site that is probably close

to desired conditions.

Reaching this condition would require hardwood and palm reduction at most pine rockland sites,

preferably by prescribed fire or mechanical removal followed by prescribed fire. Reduction of

understory densities, including hardwoods and palms, would result in better conditions for

prescribed fire. With less fuel, fires are easier to control, produce much less smoke, have less

chance of reaching the pine canopy, and result in lower fire temperatures that may be beneficial

to native herbs and make sites less prone to invasion by exotic and ruderal plant species. While

not preferred, in the absence of fire, manual or mechanical removal, herbicide application, or a

combination of techniques could be utilized to manage understory density in pine rocklands.

4.3.3 Herb Layer

Herb layers should be managed to have a diversity of native species that are indigenous to the

pine rockland community. Following recommended canopy (see Section 4.3.1) and subcanopy

(see Section 4.3.2) management guidelines should be sufficient at most sites to achieve a desired

dense and diverse herb layer. A density target is not provided here because herb layer density

and composition is so variable in pine rocklands. Canopy and subcanopy management focuses

primarily on restoring the historical fire regime at pine rocklands. Reintroduction or

augmentation of native grasses and forbs may be required at some sites. The details of this

practices will be included at the site-specific plans level in Part III of this document.

At pine rockland sites that have been subjected to fire suppression, the diversity of forbs, grasses,

and sedges can be greatly reduced. Following treatment of the canopy and subcanopy, and

reintroduction of fire, many species may reappear from a soil seed bank or dormant roots.

Following restoration by prescribed burning, many fire-suppressed sites would benefit from the

replanting of native herbs. Native species should be used that were historically on or in the

vicinity of the pine rockland fragment being restored. Lists of appropriate species can be found

online at www.regionalconservation.org in the Natives for Your Neighborhood and Floristic

Inventory of South Florida databases. Any reintroductions or augmentations should use

germplasm from pine rocklands as close to the introduction site as possible to ensure that similar

genetic material is used.

EEL Program, Management Plan, Part II – Pine Rockland (DRAFT) _____________________________________________________________________________________________________________________

Page 33

If the application of prescribed fire is absolutely impossible, there are several alternatives that are

available, although less desirable. These options include grazing, herbicide application, and

mechanical treatment. The benefits and disadvantages of these alternatives are detailed in

Section 4.6.4 of this management plan, Alternatives to Prescribed Burning.

4.3.4 Edges

Edges of pine rocklands should be managed to eliminate the occurrence of exotic pest plants

(especially Brazilian pepper, Burma reed, and natal grass) and minimize ruderal species that may

invade pine rocklands after fires.

Open areas with exposed limestone at the edges of pine rocklands (such as fire breaks) can often

be refugia for pine rockland herbs where habitat quality has degraded in the interior of sites.