Climatic zones - determination of cold resistance of plants. Winter hardiness of ornamental plants. Cold resistance zones What is climate zone z3

USDA hardiness zones

The specified climatic zoning of territories is an artificial division of places for growing plants, based on the ability of plants to survive in winter conditions. This division is based on a long-term study of winter temperatures.

The assignment of a plant to a particular zone is based on knowledge of the variety's requirements for growth and development conditions. However, even in the same zone, climatic conditions are not the same. It is well known that it is always warmer on the south side of the house, and in a place protected from the winds (for example, a courtyard or urban development), even the largest "sissies" can grow. Therefore, the given zoning of plant varieties is rather conditional.
With the help of the correct placement of plants (in a warm and calm place), as well as the use of covering materials (spunbond, foliage, spruce branches, hilling, etc.) and “laying” the shoots to the ground for the winter, you can increase the climatic zone of your site by 1-2 units. It also helps to improve the soil regime (for example, the introduction of clay on sandy soils, the introduction organic fertilizers, covering the soil with manure, mulching with sawdust, peat, etc.). Then, for example, in the conditions of the third climatic zone, it is possible to grow varieties belonging to the fourth or fifth zone without any problems. In addition, special events such as trunk whitewashing fruit trees in November, shading evergreens with covering material in February or from autumn will help to avoid frost and sunburn in conditions of sudden temperature changes and weather changes.

Table of frost resistance zones:

01.01.2012

This system (USDA-zoning) is introduced by the US Department of Agriculture but it is also used in Europe.
Hardiness zones are a certain range of temperatures in which the plant stably overwinters.
The Moscow region is traditionally referred to as the 4th zone.
That is, if zone 4 is indicated on an imported plant, it is assumed that this specimen is able to overwinter in conditions, withstanding frosts down to minus 29 degrees.
However, there are many conventions in this topic.
There is convincing evidence of the successful cultivation of plants in the Moscow region classified both in the 5th and even in the 6th zones. For example, according to many reports, ginkgo winters well in the Moscow region, although it is classified as a 5th zone.
Winter hardiness also largely depends not only on the genetic properties of the plant, but also on its current state. Past illnesses, lack of minerals or too much big harvest weaken the living organism, and its resistance decreases. Plants for which proper care, shows the maximum winter hardiness inherent in this species.
Winter hardiness changes throughout the entire hibernation period of the plant: it reaches its peak by the end of deep dormancy (end of the year in central Russia), and then decreases.
The period of transition from hibernation to the growing season is quite difficult. For example, at the beginning of spring, the bark of trees heats up during the day, and at night it cools sharply, which leads to its damage. Temperature fluctuations also negatively affect the most vulnerable areas of fruit trees - the lower parts of the trunks. Trees can be protected by whitewashing trunks at the end of winter.

Microclimatic factors affecting the winter hardiness of plants.

In addition to temperature, there are many additional factors that affect the development of plants: soil type, daylight hours, wind, humidity. It should be taken into account that the microclimate of areas within the climatic zone may not correspond to the baseline values.
Elevations, southern slopes, large reservoirs have a beneficial effect on plant growth, in contrast to lowlands and northern slopes. In the city, as a rule, the temperature is slightly higher than outside the city.
With careful observance of all the rules of agricultural technology, many trees and shrubs can be grown on the territory of colder zones in protected areas.
The plant may be suitable for five or more zones.
If your hardiness zone is colder than what is recommended for planting the selected plant, special care must be taken in deciding where to plant the seedling on the site.
Dry cold wind puts the development of evergreens at risk, as the process of evaporation from the surface of the leaves becomes more intense, and dehydration occurs. To avoid this problem, it is necessary to plant in places protected from the wind and ensure the correct development of the root system. For this, the soil must be deep, loose, permeable. Mulching works well.
wintering difficulties.
In warm winters with abundant snow cover, plants are threatened with decay - exhaustion in a dark, waterlogged, warm environment, when plants "unscheduled" consume all their nutrients.
Wetting can occur in the lowlands during the period of snow melting or prolonged thaws: melt water is not absorbed into the soil and plants lack oxygen.
Lack of oxygen and mechanical pressures often also occur due to the formation of ice crusts. Ice crust formation occurs if severe frosts occur after frequent thaws. The crusts are contact (tightly attached) or hanging (practically do not come into contact with plants, they are easy to destroy).
Bulging.
There may be frosts in the absence of snow cover or an autumn drought, or a thaw in which snow water has already been absorbed by the soil. In such conditions, freezing begins at a depth - where there is water. The layer of ice gradually increases and lifts, that is, “bulges out” the upper layers of the soil along with the plants, which leads to the breakage of the roots. Secondary rooting can save the plant from drying out, which can be stimulated with the help of timely rolling of the soil. Crops with roots capable of stretching are resistant to bulging.
Damage from winter drought (at the end of a snowless or little snowy winter with significant solar heating) poses a danger to fruit trees and shrubs in a number of regions of Russia. Under normal conditions, a stable winter cover protects the plant from drying out.

The area in which your garden plot, you can determine yourself - for this you need information about the lowest temperatures in your area over the past 10 years (you can choose a longer time period). Then we calculate the arithmetic mean of all values ​​and see what zone number it corresponds to.
Obviously, this method cannot be considered absolutely accurate. For example, anomalous temperature jumps can affect the result of calculations. In addition, the same result can be obtained both with a large spread and with minimal fluctuations in values. It is believed that the territories middle lane Russia corresponds to zone No. 5 and those below.
Below are two tables (table 1-short and more detailed table 2) by which the zone can be determined.

Table 1.
Zone Temperature
1 below - 45°C
2 from -45 to -40° С
3 -40 to -34°C
4 from -34 to -29°C
5 from -29 to -23° С
6 from -23 to -17° С
7 from -17 to -12° С
8 from -12 to -7° С
9 -7 to -1°C
10 from -1 to +5° С

Table 2.
Hardiness zone From To
0 a< -53.9°C
b -51.1°C -53.9°C
1a -48.3°C -51.1°C
b -45.6°C -48.3°C
2 a -42.8°C -45.6°C
b -40°C -42.8°C
3 a -37.2°C -40°C
b -34.4°C -37.2°C
4 a -31.7°C -34.4°C
b -28.9°C -31.7°C
5 a -26.1°C -28.9°C
b -23.3°C -26.1°C
6 a -20.6°C -23.3°C
b -17.8°C -20.6°C
7 a -15°C -17.8°C
b -12.2°C -15°C
8 a -9.4°C -12.2°C
b -6.7°C -9.4°C
9 a -3.9°C -6.7°C
b -1.1°C -3.9°C
10 a +1.7°C -1.1°C
b +1.7°C +4.4°C
11 a +4.4°C +7.2°C
b +7.2°C +10°C
12 a +10°C +12.8°C
b > +12.8°C

According to kr.ru

Russia is a country that occupies a huge area. Many peoples and ethnic groups live on its territory. But, in addition to this, it is also subdivided into various climatic zones. Depending on this, various flora and fauna settle in different parts of the country. What are the climatic zones of Russia, according to what criteria is the division and what are the features of these zones - read about all this in the presented article.

Total number of climate zones

Initially, you need to understand how many climatic zones exist in general. So, in nature there are four of them (the countdown comes from the equator line):

• Tropical.
• Subtropical.
• Moderate.
• Polar

Generally speaking, the division into climatic zones occurs in accordance with the average temperature of the surface heating by the sun's rays. At the same time, it should be noted that such zoning took place on the basis of long-term observations and conclusions drawn from analytical data.

About the climatic zones of Russia

What are the climatic zones of Russia? The territory of the country is very large, which allowed it to be located in three of them. So, if we talk about belts, then there are three of them on the territory of Russia - moderate, arctic and subarctic. However, the natural and climatic zones of Russia are divided into meridians, of which there are 4 on the territory of the state, related to the 20th, 40th, 60th and 80th meridians. That is, there are four climatic zones, the fifth is called special.

Table of climatic zones

There are 4 climatic zones in Russia. The table is presented for easier perception of information:

Considering the climatic zones of Russia, it should be noted that most of the country is located in the arctic and subarctic zones. Also, quite a lot of territories occupy a moderate zone. There are not so many subtropics, it is less than 5% of the entire territory of Russia.

arctic climate

Considering the climatic zones of Russia should begin with the Arctic climate. It is characteristic for a special, and also partially 4th zone. Mostly arctic deserts and tundras are located here. The soil hardly warms up Sun rays they just glide over the surface, which prevents the flora from growing and developing. The fauna is also scarce, the reason for everything is the lack of food. Winter takes most time, which is about 10 months. During the summer period, the soil does not have time to warm up, since the heat in the region of 0- + 3 ° C lasts no more than a couple of weeks. During the polar night, the temperature can drop to -60 °C. Precipitation is practically absent, it can only be in the form of snow.

subarctic climate

Widely distributed in Russia. So, it includes the 4th zone, as well as partially special and third. Winter is also long, cold, but less severe. Summer is short, but the average temperature is 5 degrees higher. Arctic cyclones cause strong winds, cloudiness, there are precipitations, but not heavy.

Temperate climate

3rd and also 2 climate zone Russia belongs to a temperate climate. Covers most of the country. The seasons here are pronounced, there are spring, summer, autumn and winter. Temperatures can range from +30°C in summer to -30°C in winter. For convenience, scientists divide this zone of Russia into 4 more:

• Moderate continental. Summer is hot, winter is cold. natural areas can replace each other from the steppes to the taiga. Atlantic air masses prevail.
• Continental. The temperature fluctuates from -25 °С in winter to +25 °С in summer. A large number of precipitation. The zone is formed mainly by western air masses.
• Sharply continental. Partly cloudy, little precipitation. In summer, the soil warms up well, in winter it freezes deeply.
• Maritime as well as monsoonal climates. Strong winds are characteristic, which are called monsoons. Precipitation is heavy and there may be flooding. Summer is not hot, the average air temperature is +15...+20 °С. Winters are very cold, the air temperature can drop to -40 °C. In coastal areas, winter and summer are smoother.

subtropical climate

1 climatic zone of Russia partially covers a small area of ​​the country in the region of the Caucasus Mountains. Summer here is long, but not hot. In winter, the temperature does not fall below 0 °C. Due to the proximity of the mountains, there is quite a lot of precipitation, they are plentiful.

There are no tropics and the equatorial zone on the territory of Russia.

Road-climatic zones

Few people know, but there are also road-climatic zones in Russia. They are divided according to the features of the building. highways for a certain territory (depending on temperatures, precipitation and other climatic indicators). In this section, you can find 5 zones.

The benefits of division into climatic zones

Why single out the climatic zones of Russia? Table 1 and Table 2 indicate that there are many of them. All this is for convenience. Thus, this division is important for many areas of activity and knowledge. Most often, such zoning is important:

• For tourism business, resort planning.
• During the construction of buildings, roads (including railways), designing communications.
• When assessing the possibility of living in the area of ​​people.
• When planning the extraction of minerals, natural resources.
• When organizing agriculture, farming.

Well, speaking in general, knowledge of climatic zones helps many people improve their lives in various parts of the country. This knowledge helps many to optimize and master this or that territory for living. For example, cold areas are expensive, in a temperate climate it is best to breed livestock and grow useful vegetation.

Zoning cultivated plants, is directly related to the definition of the so-called frost resistance zones - climatic regions, to which they can correspond, as acceptable, from the position of laying extensive (industrial) plantations. This concept is more rigorous than the general possibility for the introduction various kinds plants, which allows more extensive experiments in a favorable microclimate.

At the moment, the generally accepted international (American) classification is the USDA zones, containing 11 such gradients with transitional subzones a) and b) (), which, despite its limited flexibility, is still quite often used in our country as a guide.
Most of the territory of the temperate zone (middle zone), with active agricultural activity, fits into the indicators of 3-7 climatic zones of frost resistance. A broad perspective for the introduction of various foreign cultures of a temperate climate begins with zone 5, which corresponds to the average scale of the absolute minimums: −23.3 °C .. −28.9 °C

There is confusion in understanding these critical indicators for determining frost resistance zones, which are used in agrometeorology for agroclimatic zoning.
The first fundamental calculation parameter is the indicator of the absolute annual minimum, which characterizes the short-term (from several hours or more) setting of cold fronts, which can lead to significant freezing or complete death of the plant. It can only be considered in the context of a limited time frame - or for the period of all available on this moment observations (often, this is no more than 60-80 years of history), or within the initially set limits: the last climatic norm - a period of 30 years of observations, or an arbitrarily taken period - 20, 40 or more years. To take into account the latest dynamics of climate change, a period of up to 10-20 years is considered. Given the above, an answer in the spirit of “we don’t get -40” is not correct by definition, in general case, such words do not characterize anything.
More indicative is another calculated parameter - the average of the absolute minimums (as a rule, it is 1.5 times less than the previous indicator). To calculate it, absolute minima are taken for each year, for the required period (as a rule, for the last 10-20 years of observations) and averaged. This parameter and is taken as the unit of account when determining USDA zones.

Consider an example.
Let's take the data of the absolute minimum (indicator Tn) for the State Botanical Garden (GBS) of Moscow (the observation station at the All-Russian Exhibition Center is located a few kilometers from the southern entrance), as a data source we will use the resource - http://rp5.ru/, look in the sections: Weather archive at the weather station / Weather statistics:
2005 .. -21.5 °C
2006 .. -30.8 °C
2007 .. -23.0 °C
2008 .. -18.3 °C
2009 .. -22.1 °C
2010 .. -25.9 °C
2011 .. -26.4 °C
2012 .. -28.5 °C
2013 .. -18.3 °C
2014 .. -25.4 °C

We get: the average of the absolute minimums over the last 10 years of observations will be (add all the values ​​\u200b\u200band divide by 10): -24 ° C
According to the table of values, we determine for the GBS of Moscow the correspondence to the frost resistance zone 5b, which is typical only for the microclimate conditions of the city (the total frost resistance zone for the Moscow region will already be an order of magnitude lower).

This zone of frost resistance, if we take into account the latest climatic norm - 30 years of observations, passes, approximately, along the border: Minsk - Gomel - Bryansk - Kursk - Belgorod - Voronezh, which is the border, for example, of a possible industrial culture of sweet cherries, but what else not sufficient for commercial apricot cultivation (varieties derived from the common apricot genotype), or walnut.
One should always distinguish general recommendations on the introduction (introduction) of certain plant species within one climatic region - frost resistance zone, and the possibility of a specific microclimate. As a rule, within one generalized zone of frost resistance, one can always find (identify): both more favorable conditions, already transitional, for the next - more favorable neighboring zone, and conditions with burdens, which should be taken adjusted for one zone below. Also, there is not the same thing, the frost resistance of a tree considered as part of a forest biocenosis (forest population) and a separate open personal plot. The forest, in itself, is already the fundamental basis for the formation of the microclimate and other factors that contribute to a more adequate acclimatization of the species.
It should be taken into account that many plants from other regions show an increased sensitivity to environmental conditions that are uncharacteristic for them (humidity regimes, solar radiation, the nature of the change of seasons, etc.), which affects, among other things, the ability to unleash the full potential of inherent genotypic frost resistance. For this reason, often, in foreign nurseries, in relation to such foreign crops, two zones of frost resistance are indicated simultaneously - one for natural growing conditions (within its distribution area), and the second - in the introduction of specific local conditions, which, nominally (by default, ) is set to -1 zone below.

Work on reseeding (reproduction in generations) under new conditions of introduced breeds, as a rule, serves the purpose of normalizing (opening the full potential) of genotypically inherent frost resistance, which is a realistic task for many plants. But still, this reserve should not be exaggerated unnecessarily. In the general case, it cannot be higher than the frost resistance of a particular species, which manifests itself under natural conditions along the northern border of its distribution, and for sure, it can be most fully revealed only in native conditions. So, for example, depending on the place of growth (nature of naturalization), as well as the source of seed material, in a situation of full passage of all phases of vegetative development, the manifested frost resistance of the Manchurian walnut, allowing it to go through the stage of winter dormancy without significant damage to the aerial part, can vary from - 44 °C to -52 °C and more degrees. At the same time, the ability, let's move on to the example of a walnut, to endure winters with temperatures down to -40 ° C in places of industrial culture (southern Ukraine, for example), and somewhere in the Moscow region, is completely different.
It would be more correct, as recommended by many reference books, when determining frost resistance zones, to take into account another important interconnected indicator - the sum of active temperatures for the growing season (for temperate zone, most often they are guided by the sum of positive temperatures of more than +10 ° C), but this is a topic for a separate discussion.

Mar 3, 2014 Alexei

The individual features of the development of each plant, as well as its distribution area, are primarily determined by the main characteristics environment such as temperature and rainfall. Therefore, when acquiring new plants for the garden, it is very important to determine their need for the amount of heat needed during the growing season, as well as the conditions temperature regime during dormancy, for favorable wintering and successful reproduction. Such indicators for plants are: cold resistance, frost resistance and winter hardiness.

Cold resistance and frost resistance of plants reflects their viability at low temperatures: cold resistance - up to 0 ° C, and frost resistance - from 0 ° C and below.

The winter hardiness of plants is a kind of indicator of the result of wintering plants, reflecting their reaction to the sum of any changes in environmental characteristics in winter: precipitation, wind, icing, thaws, frosts.

Freeze or NOT freeze...

Combining plant species in accordance with their temperature requirements, nurseries of various countries have created schematic maps, according to which it is possible to determine the frost resistance of representatives of a particular species, depending on the region of growth. Each of the zones marked on the map falls within the temperature range characteristic for the viability of the determined plant species, taking into account a short-term decrease in the lower temperatures that are safe for this species.

However, it should be noted that in any region tied to a certain frost resistance zone, there may be exceptions not only in terms of climatic characteristics (as a microclimate), but also depending on the growing conditions of a particular plant. For example, the same species, tied to the same zone, grown on an open hillside, can freeze, while its counterpart, on the edge of the forest, calmly overwinter under leaf litter. In addition, the mapping of plant hardiness is based on the readings of the lowest temperatures in the area over the past decade, which means that the figures obtained in the next decade may be different. Thus, when determining the frost resistance of plants according to the map, one should not forget that such a division - conditionally and completely rely on it - is impossible. It is better to collect as much information as possible from various sources, talking on gardening forums, visiting flower growers' websites, as well as from printed publications: books, newspapers and magazines. However, in this case, it must be borne in mind that some varieties of the same species may differ significantly in frost resistance.

Hardiness zones

1st — from -46°C and below

2nd - from -37ºС to -46ºС

3rd - from -34ºС to -37ºС

4th - from -28ºС to -34°С

5th - from -23°С to -28°С

6th - from -18°С to -23°С

7th — from -12°С to -18°С

8th — from -7° to -12°С

And suddenly it overwinter...

In any case, choosing for your garden plants recommended for zones located to the south, you can try to compensate for the lack of heat by preparing in advance the conditions aimed at the successful wintering of the new candidate. Such measures include: feeding plants with potash fertilizers (in August - September), increasing air humidity (spraying plants, planting close to natural and), improving illumination and hardening.

True, if everything is clear with illumination (you just need to choose the brightest place in the garden), then hardening is a lengthy process that requires a lot of time and individual approach to every plant. The success of this procedure will be complete only when properly combined with other methods of care: timely transplantation and correct pruning plants, the use of fertilizers, systematic and high-quality watering. And all this in combination with normal weather conditions. Under adverse environmental conditions, most representatives of the flora are generally able to go into a state of forced rest, while maintaining viability, which in itself is not very good, because in this case, a weakened and unprepared plant for winter can simply die as a result of wintering. This is especially true for heat-loving southerners - sometimes a period of relative rest is observed in them even with slight drops in temperature. That is why, for example, roses give gardeners so much trouble - during thaws, they quickly begin to wake up and release leaves, which then freeze slightly. As for plants native to areas with frosty winters, for such representatives, a state of deep dormancy is a common phenomenon caused by necessity, but this does not save them from return frosts, to which, however, most plants in general are subject.

We increase winter hardiness

But if return frosts, despite the cold resistance of plants, can damage the buds, flowers and leaves of a specimen of any age, then the stems, roots and rhizomes of well-rooted plants suffer less with age. The growing bark becomes more durable, and the root system penetrating deep into the ground not only freezes less, but also better provides the entire plant with nutrients, strengthening its immunity and increasing winter hardiness. Given this circumstance, young plants, especially those planted in autumn, must be carefully covered even in the southern regions of Russia. This is especially true for wintergreen and evergreen species wintering under snow. In snowless winters, they definitely need it, which, in the case of tall specimens, is not easy to build. It should be noted that the snow cover generally facilitates wintering for many plants. Its presence protects the soil surface from thawing during short-term thaws, thereby reducing the risk of damage to the root system from sudden temperature changes; although an abundance of snow can threaten any plants with elementary decay due to the fact that melt water stagnates near the roots, simply not having time to soak into the frozen ground.

Sometimes it happens…

Having acclimatized, some species try to adapt to new conditions, which may affect their external phenological characteristics. For example, shrubs that freeze during the wintering period, to the ground surface, such shrubs as: large-leaved hydrangea, and, in more severe wintering conditions, become semi-shrubs, and the leaves of the arctic cinquefoil, introduced into a warmer region, lose part of the dense pubescence covering their leaves.

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